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PubMed1999

The structure and dynamics of rat apo-cellular retinol-binding protein II in solution: comparison with the X-ray structure.

The structure and dynamics of rat apo-cellular retinol binding protein II (apo-CRBP II) in solution has been determined by multidimensional NMR analysis of uniformly enriched recombinant rat 13C, 15N-apo-CRBP II and 15N-apo-CRBP II. The final ensemble of 24 NMR structures has been calculated from 3274 conformational restraints or 24.4 restraints/residue. The average root-mean-square deviation of the backbone atoms for the final 24 structures relative to their mean structure is 1.06 A. Although the average solution structure is very similar to the crystal structure, it differs at the putative entrance to the binding cavity, which is formed by the helix-turn-helix motif, the betaC-betaD turn and the betaE-betaF turn. The mean coordinates of the main-chain atoms of amino acid residues 28-38 are displaced in the solution structure relative to the crystal structure. The side-chain of F58, located on the betaC-betaD turn, is reoriented such that it interacts with L37 and no longer blocks entry into the ligand-binding pocket. Residues 28-35, which form the second helix of the helix-turn-helix motif in the crystal structure, do not exhibit a helical conformation in the solution structure. The solution structure of apo-CRBP II exhibits discrete regions of backbone disorder which are most pronounced at residues 28-32, 37-38 and 73-76 in the betaE-betaF turn as evaluated by the consensus chemical shift index, the root-mean-square deviation, amide 1H exchange rates and 15N relaxation studies. These studies indicate that fluctuations in protein conformation occur on the microseconds to ms time-scale in these regions of the protein. Some of these exchange processes can be directly observed in the three-dimensional 15N-resolved NOESY spectrum. These results suggest that in solution, apo-CRBP II undergoes conformational changes on the microseconds to ms time-scale which result in increased access to the binding cavity.

Amides↗
PubMed1994

NMR solution structure of the C-terminal fragment 255-316 of thermolysin: a dimer formed by subunits having the native structure.

The solution structure of the C-terminal fragment 255-316 of thermolysin has been determined by two-dimensional proton NMR methods. For this disulfide-free fragment there was a previous proposal according to which it would fold into a stable helical structure forming a dimer at concentrations above 0.06 mM. A complete assignment of the proton NMR resonances of the backbone and amino acid side chains of the fragment was first performed using standard sequential assignment methods. On the basis of 729 distance constraints derived from unambiguously assigned nuclear Overhauser effect (NOE) proton connectivities, the three-dimensional structure of a monomeric unit was then determined by using distance geometry and restrained molecular dynamic methods. The globular structure of fragment 255-316 of thermolysin in solution, composed of three helices, is largely coincident with that of the corresponding region in the crystallographic structure of intact thermolysin [Holmes, M. A., & Matthews, B. W. (1982) J. Mol. Biol. 160, 623-639]. This fact allowed identification as intersubunit of up to 52 NOE cross correlations, which were used to dock the two subunits into a symmetric dimer structure. The obtained dimeric structure served as the starting structure in a final restrained molecular dynamic calculation subjected to a total of 1562 distance constraints. In the resulting dimeric structure, the interface between the two subunits, of a marked hydrophobic character, coincides topologically with the one between the 255-316 fragment and the rest of the protein in the intact enzyme. The present work decisively shows that the thermolysin fragment 255-316 can attain a stable and nativelike structure independently of the rest of the polypeptide chain. Considering that the thermolysin molecule is constituted of two structural domains of equal size (residues 1-157 and 158-316), the results of this study show that autonomously folding units can be substantially smaller than entire domains.

Amino Acid Sequence↗
PubMed2002

SUPFAM--a database of potential protein superfamily relationships derived by comparing sequence-based and structure-based families: implications for structural genomics and function annotation in genomes.

Members of a superfamily of proteins could result from divergent evolution of homologues with insignificant similarity in the amino acid sequences. A superfamily relationship is detected commonly after the three-dimensional structures of the proteins are determined using X-ray analysis or NMR. The SUPFAM database described here relates two homologous protein families in a multiple sequence alignment database of either known or unknown structure. The present release (1.1), which is the first version of the SUPFAM database, has been derived by analysing Pfam, which is one of the commonly used databases of multiple sequence alignments of homologous proteins. The first step in establishing SUPFAM is to relate Pfam families with the families in PALI, which is an alignment database of homologous proteins of known structure that is derived largely from SCOP. The second step involves relating Pfam families which could not be associated reliably with a protein superfamily of known structure. The profile matching procedure, IMPALA, has been used in these steps. The first step resulted in identification of 1280 Pfam families (out of 2697, i.e. 47%) which are related, either by close homologous connection to a SCOP family or by distant relationship to a SCOP family, potentially forming new superfamily connections. Using the profiles of 1417 Pfam families with apparently no structural information, an all-against-all comparison involving a sequence-profile match using IMPALA resulted in clustering of 67 homologous protein families of Pfam into 28 potential new superfamilies. Expansion of groups of related proteins of yet unknown structural information, as proposed in SUPFAM, should help in identifying 'priority proteins' for structure determination in structural genomics initiatives to expand the coverage of structural information in the protein sequence space. For example, we could assign 858 distinct Pfam domains in 2203 of the gene products in the genome of Mycobacterium tubercolosis. Fifty-one of these Pfam families of unknown structure could be clustered into 17 potentially new superfamilies forming good targets for structural genomics. SUPFAM database can be accessed at http://pauling.mbu.iisc.ernet.in/~supfam.

Animals↗
PubMed1998

Sequences annotated by structure: a tool to facilitate the use of structural information in sequence analysis.

With the aim of bridging the gap between protein sequence and structural analyses, we have developed a tool to aid the identification of new protein sequences by recognizing distant homologues using structural information. The tool generates sequence annotated by structure (SAS) files, applying structural information derived from structural analyses to a given protein sequence. A World Wide Web interface allows a given sequence to be submitted either for structural annotation or, where its structure is unknown, for search and alignment against sequences of known structure. In both cases, SAS will colour residues in the sequence of known structure according to a selection of properties, including secondary structure, interatomic contacts and active site information. SAS can also be used to inspect properties of a single structure.

Amino Acid Sequence↗
PubMed2003

Multiple structural alignment for distantly related all beta structures using TOPS pattern discovery and simulated annealing.

Topsalign is a method that will structurally align diverse protein structures, for example, structural alignment of protein superfolds. All proteins within a superfold share the same fold but often have very low sequence identity and different biological and biochemical functions. There is often significant structural diversity around the common scaffold of secondary structure elements of the fold. Topsalign uses topological descriptions of proteins. A pattern discovery algorithm identifies equivalent secondary structure elements between a set of proteins and these are used to produce an initial multiple structure alignment. Simulated annealing is used to optimize the alignment. The output of Topsalign is a multiple structure-based sequence alignment and a 3D superposition of the structures. This method has been tested on three superfolds: the beta jelly roll, TIM (alpha/beta) barrel and the OB fold. Topsalign outperforms established methods on very diverse structures. Despite the pattern discovery working only on beta strand secondary structure elements, Topsalign is shown to align TIM (alpha/beta) barrel superfamilies, which contain both alpha helices and beta strands.

Protein Structure, Secondary↗
PubMed2004

Use of a structural alphabet for analysis of short loops connecting repetitive structures.

BACKGROUND: Because loops connect regular secondary structures, analysis of the former depends directly on the definition of the latter. The numerous assignment methods, however, can offer different definitions. In a previous study, we defined a structural alphabet composed of 16 average protein fragments, which we called Protein Blocks (PBs). They allow an accurate description of every region of 3D protein backbones and have been used in local structure prediction. In the present study, we use this structural alphabet to analyze and predict the loops connecting two repetitive structures. RESULTS: We first analyzed the secondary structure assignments. Use of five different assignment methods (DSSP, DEFINE, PCURVE, STRIDE and PSEA) showed the absence of consensus: 20% of the residues were assigned to different states. The discrepancies were particularly important at the extremities of the repetitive structures. We used PBs to describe and predict the short loops because they can help analyze and in part explain these discrepancies. An analysis of the PB distribution in these regions showed some specificities in the sequence-structure relationship. Of the amino acid over- or under-representations observed in the short loop databank, 20% did not appear in the entire databank. Finally, predicting 3D structure in terms of PBs with a Bayesian approach yielded an accuracy rate of 36.0% for all loops and 41.2% for the short loops. Specific learning in the short loops increased the latter by 1%. CONCLUSION: This work highlights the difficulties of assigning repetitive structures and the advantages of using more precise descriptions, that is, PBs. We observed some new amino acid distributions in the short loops and used this information to enhance local prediction. Instead of describing entire loops, our approach predicts each position in the loops locally. It can thus be used to propose many different structures for the loops and to probe and sample their flexibility. It can be a useful tool in ab initio loop prediction.

Computational Biology↗
PubMed1995

Refined solution structure of the Tyr41-->His mutant of the M13 gene V protein. A comparison with the crystal structure.

The three-dimensional solution structure of mutant Tyr41-->His of the single-stranded DNA binding protein encoded by gene V of the filamentous bacteriophage M13 has been refined in two stages. The first stage involved the collection of additional NOE-based distance constraints, which were then used in eight cycles of back-calculations and structure calculations. The structures of the gene V protein dimers were calculated using simulated annealing, employing restrained molecular dynamics with a geometric force field. In the second stage of the refinement procedure, solvent was explicitly included during the dynamic calculations. A total of 30 structures was calculated for the protein, representing its solution structure in water. The first calculation step significantly improved the convergence of the structures, whereas the subsequent simulations in water made the structures physically more realistic. This is, for instance, illustrated by the number of hydrogen bonds formed in the molecule, which increased considerably upon going to aqueous solution. It is shown that the solution structure of the mutant gene V protein is nearly identical to the crystal structure of the wild-type molecule, except for the DNA-binding loop (residues 16-28). This antiparallel beta-hairpin is twisted and partially folded back towards the core of the protein in the NMR structure, whereas it is more extended and points away from the rest of the molecule in the X-ray structure. Unrestrained molecular dynamics calculations suggest that this latter conformation is energetically unstable in solution.

Amino Acid Sequence↗
PubMed2001

FUGUE: sequence-structure homology recognition using environment-specific substitution tables and structure-dependent gap penalties.

FUGUE, a program for recognizing distant homologues by sequence-structure comparison (http://www-cryst.bioc.cam.ac.uk/fugue/), has three key features. (1) Improved environment-specific substitution tables. Substitutions of an amino acid in a protein structure are constrained by its local structural environment, which can be defined in terms of secondary structure, solvent accessibility, and hydrogen bonding status. The environment-specific substitution tables have been derived from structural alignments in the HOMSTRAD database (http://www-cryst.bioc. cam.ac.uk/homstrad/). (2) Automatic selection of alignment algorithm with detailed structure-dependent gap penalties. FUGUE uses the global-local algorithm to align a sequence-structure pair when they greatly differ in length and uses the global algorithm in other cases. The gap penalty at each position of the structure is determined according to its solvent accessibility, its position relative to the secondary structure elements (SSEs) and the conservation of the SSEs. (3) Combined information from both multiple sequences and multiple structures. FUGUE is designed to align multiple sequences against multiple structures to enrich the conservation/variation information. We demonstrate that the combination of these three key features implemented in FUGUE improves both homology recognition performance and alignment accuracy.

Algorithms↗
PubMed1994

Structure and dynamics of the antitumor drugs nogalamycin and disnogalamycin complexed to d(CGTACG)2: comparison of crystal and solution structures.

The nuclear magnetic resonance (NMR) solution structures of the 2:1 complexes of nogalamycin-d(CGTACG)2 (Ng-CGTACG) and disnogalamycin-d(CGTACG)2 (DNg-CGTACG) have been determined by a quantitative treatment of two-dimensional nuclear Overhauser effect (2D-NOE) crosspeak intensities. The 1.3 A resolution crystal structure of the 2:1 complex of Ng-CGTACG was used as a starting model for refinement using the procedure, SPEDREF [Robinson and Wang, Biochemistry 31 (1992) 3524-3533], which incorporates full matrix relaxation theory and simulated annealing minimization. The refined solution structures have R-factors of 16.1 and 19.6% between the observed and simulated NOEs for Ng-CGTACG and DNg-CGTACG, respectively. The refined NMR structures retain major features of the crystal structure in which the elongated aglycone chromophore is intercalated between the CpG steps with its nogalose and aminoglucose lying in the minor and major grooves, respectively. The root mean square deviation between the solution and crystal structure for the complexes is 1.01 A (Ng-CGTACG) and 1.20 A (DNg-CGTACG) for the drug, plus the three base pairs surrounding the drug, indicating a very similar local structure at the intercalation site. In the NMR structure, the two G:C Watson-Crick base pairs (C1:G12 and G2:C11) that wrap around the aglycone have large buckles, as do those seen in the crystal structure. There is a 22 degree bend at the T3-A4 step in the refined solution structure. This rearrangement of the solution conformation is likely due to the absence of crystal packing. Specific hydrogen bonds between the drug and G:C bases in both grooves of the helix are preserved in the solution structure. A separate study of the 2:1 complex at low pH showed that the terminal G-C base pairing is destabilized.

Crystallography, X-Ray↗
PubMed2004

Effect of pH on the stability and structure of yeast hexokinase A. Acidic amino acid residues in the cleft region are critical for the opening and the closing of the structure.

pH and salts have a marked effect on the stability, structure, and function of many globular proteins due to their ability to influence the electrostatic interactions. In this work, calorimetry, CD, and fluorescence studies have been carried out to understand the pH-dependent conformational changes of the two-domain protein yeast hexokinase A. In conjunction with the crystal structural data available, the present results have enabled the complete characterization and analysis of the pH-dependent conformational changes of the enzyme that have strong implications in understanding its structure-function relationship. The calorimetric profiles show a single thermal transition in the acidic pH range, whereas two independent transitions were observed in the alkaline pH range, suggesting the structural merger of the domains at the acidic pH. Comparison of the thermal transitions at pH 8.5 studied by different techniques suggests that the first transition corresponds to the smaller domain, and the second transition corresponds to the larger domain. The acid-denatured state of hexokinase A has high secondary structure content with little or no tertiary interactions and binds to the hydrophobic dye 8-anilinonaphthalene-1-sulfonic acid, suggesting that it is a molten globule-like state, whereas the alkali-denatured state is less structured than the acid-denatured state but more structured than the urea-denatured state, suggestive of a premolten globule-like state. Structural analysis using the published hexokinase B structure as well as the hexokinase A structure with the revised amino acid sequence in conjunction with the results obtained by us suggests that the ionization state of the acidic residues at the active site could regulate domain movements that are responsible for the opening and the closure of the cleft between the two domains and in turn affect the structure and function of the enzyme.

Acids↗
PubMed1998

The solution conformation of a carbocyclic analog of the Dickerson-Drew dodecamer: comparison with its own X-ray structure and that of the NMR structure of the native counterpart.

The NMR conformation of a carbocyclic analog of the Dickerson-Drew dodecamer [d(CGC-GAAT*T*CGCG)]2 containing 6'-alpha-Me carbocyclic thymidines (T*) has been determined and compared with that of its X-ray structure. The solution structure of the 6'-alpha-Me carbocyclic thymidine modified duplex has also been compared with the solution structure of the corresponding unmodified Dickerson-Drew duplex solved by us under the same experimental conditions. The NMR structures have been based on 24 experimental distance and torsion constraints per residue for [d(CGCGAAT*T*CGCG)]2 (1) and on 21 constraints per residue for the natural counterpart. In general, both final NMR structures are more close to the B-type DNA. The cyclopentane moieties of the carbocyclic thymidine residues adopt C1'-exo B-DNA type puckers (the phase angles P = 136-139 degrees and the puckering amplitudes psi = 36-37 degrees) that are close to their previously published crystal C1'-exo or C2'-endo puckers. The main differences between the two NMR structures are for beta(T*8) and epsilon, xi(T*7) backbone torsions (27-50 degrees ), for basepair twist for the 7-8 and 8-9 basepair steps (5-6 degrees), tilt for the 8-9 step (7 degrees), roll for the 7-8 step (7 degrees), shift for the 7-8 step (0.9A) and slide for the 9-10 step (0.6A). The relatively small deviations of helical structure parameters lead to structural isomorphism of these duplexes in aqueous solutions (atomic RMSD = 1.0A). The difference of the minor groove widths (less than 0.7A) in the core part of the modified duplex in comparison with the native one is much smaller than the difference between the X-ray structures of these duplexes. A detailed comparison of NMR and X-ray structure parameters showed significant monotonic differences (0.9-2.5A) for all basepair slides in both duplexes. Deviations between NMR and X-ray structure parameters for the modified duplex were also found for basepair tilt of the 4-5 step (13 degrees), rolls for the 8-9 and 10-11 steps (16 and 19 degrees), twist of the 3-4 step (8 degrees) and shift of the 9-10 step (0.9A).

Acids, Carbocyclic↗
PubMed1995

Rapid protein structure classification using one-dimensional structure profiles on the bioSCAN parallel computer.

Rapid growth of protein structures database in recent years requires an effective approach for objective comparison and classification of deposited protein structures. We describe a novel method for structure comparison and classification based on the alignment of one-dimensional structure profiles. These profiles are obtained by calculating the OCCO pseudodihedral angles (formed by O-C-C-O atoms of carbonyl groups of consecutive amino acid residues) from protein three-dimensional coordinates. These angle measurements are then converted into a 24 letter alphabet, and the protein structures are represented by sequences of letter from this alphabet. The BioSCAN parallel computer, designed for primary sequence alignment, is used to rapidly align and classify these one-dimensional structure profiles. We have developed and implemented weighted scoring matrix to identify structural classes based on commonly found structural motifs. The results of our experiments are in good agreement with the traditional protein structure classification schemes. One-dimensional structure profiles significantly improve efficiency of structure comparison and classification.

Algorithms↗
PubMed2001

Secondary structure prediction and structure-specific sequence analysis of single-stranded DNA.

DNA sequence analysis by oligonucleotide binding is often affected by interference with the secondary structure of the target DNA. Here we describe an approach that improves DNA secondary structure prediction by combining enzymatic probing of DNA by structure-specific 5'-nucleases with an energy minimization algorithm that utilizes the 5'-nuclease cleavage sites as constraints. The method can identify structural differences between two DNA molecules caused by minor sequence variations such as a single nucleotide mutation. It also demonstrates the existence of long-range interactions between DNA regions separated by >300 nt and the formation of multiple alternative structures by a 244 nt DNA molecule. The differences in the secondary structure of DNA molecules revealed by 5'-nuclease probing were used to design structure-specific probes for mutation discrimination that target the regions of structural, rather than sequence, differences. We also demonstrate the performance of structure-specific 'bridge' probes complementary to non-contiguous regions of the target molecule. The structure-specific probes do not require the high stringency binding conditions necessary for methods based on mismatch formation and permit mutation detection at temperatures from 4 to 37 degrees C. Structure-specific sequence analysis is applied for mutation detection in the Mycobacterium tuberculosis katG gene and for genotyping of the hepatitis C virus.

5' Untranslated Regions↗
PubMed2003

Common Structural Cliques: a tool for protein structure and function analysis.

Proposed is a method for locating functionally relevant atoms in protein structures and a representation of spatial arrangements of these atoms allowing for a flexible description of active sites in proteins. The search method is based on comparison of local structure features of proteins that share a common biochemical function. The method does not depend on overall similarity of structures and sequences of compared proteins or on previous knowledge about functionally relevant residues. The compared protein structures are condensed to a graph representation, with atoms as nodes and distances as edge labels. Protein graphs are then compared to extract all possible Common Structural Cliques. These cliques are merged to create Structural Templates: graphs that describe structural analogies between compared proteins. Structures of serine endopeptidases were compared in pairs using the presented algorithm with different geometrical parameters. Additionally, a Structural Template was extracted from the structures of aminotransferases, two different proteins that catalyze the same type of chemical reaction. The results presented show that the method works efficiently even in the case of large protein systems and allows for extraction of common structural features from proteins catalyzing a particular chemical reaction, but that evolved from different ancestors by convergent evolution.

Algorithms↗
PubMed2002

Structure of a yeast hypothetical protein selected by a structural genomics approach.

Yeast hypothetical protein YBL036C (SWISS-PROT P38197), initially thought to be a member of an 11-protein family, was selected for crystal structure determination since no structural or functional information was available. The structure has been determined independently by MIR and MAD methods to 2.0 A resolution. The MAD structure was determined largely through automated model building. The protein folds as a TIM barrel beginning with a long N-terminal helix, in contrast to the classic triose phosphate isomerase (TIM) structure, which begins with a beta-strand. A cofactor, pyridoxal 5'-phosphate, is covalently bound near the C-terminal end of the barrel, the usual active site in TIM-barrel folds. A single-domain monomeric molecule, this yeast protein resembles the N-terminal domain of alanine racemase or ornithine decarboxylase, both of which are two-domain dimeric proteins. The yeast protein has been shown to have amino-acid racemase activity. Although selected as a member of a protein family having no obvious relationship to proteins of known structure, the protein fold turned out to be a well known and widely distributed fold. This points to the need for a more comprehensive base of structural information and better structure-modeling tools before the goal of structure prediction from amino-acid sequences can be realised. In this case, similarity to a known structure allowed inferences to be made about the structure and function of a widely distributed protein family.

Alanine Racemase↗
PubMed2002

Structural similarity to link sequence space: new potential superfamilies and implications for structural genomics.

The current pace of structural biology now means that protein three-dimensional structure can be known before protein function, making methods for assigning homology via structure comparison of growing importance. Previous research has suggested that sequence similarity after structure-based alignment is one of the best discriminators of homology and often functional similarity. Here, we exploit this observation, together with a merger of protein structure and sequence databases, to predict distant homologous relationships. We use the Structural Classification of Proteins (SCOP) database to link sequence alignments from the SMART and Pfam databases. We thus provide new alignments that could not be constructed easily in the absence of known three-dimensional structures. We then extend the method of Murzin (1993b) to assign statistical significance to sequence identities found after structural alignment and thus suggest the best link between diverse sequence families. We find that several distantly related protein sequence families can be linked with confidence, showing the approach to be a means for inferring homologous relationships and thus possible functions when proteins are of known structure but of unknown function. The analysis also finds several new potential superfamilies, where inspection of the associated alignments and superimpositions reveals conservation of unusual structural features or co-location of conserved amino acids and bound substrates. We discuss implications for Structural Genomics initiatives and for improvements to sequence comparison methods.

Amino Acid Sequence↗
PubMed2000

Automated search of natively folded protein fragments for high-throughput structure determination in structural genomics.

Structural genomic projects envision almost routine protein structure determinations, which are currently imaginable only for small proteins with molecular weights below 25,000 Da. For larger proteins, structural insight can be obtained by breaking them into small segments of amino acid sequences that can fold into native structures, even when isolated from the rest of the protein. Such segments are autonomously folding units (AFU) and have sizes suitable for fast structural analyses. Here, we propose to expand an intuitive procedure often employed for identifying biologically important domains to an automatic method for detecting putative folded protein fragments. The procedure is based on the recognition that large proteins can be regarded as a combination of independent domains conserved among diverse organisms. We thus have developed a program that reorganizes the output of BLAST searches and detects regions with a large number of similar sequences. To automate the detection process, it is reduced to a simple geometrical problem of recognizing rectangular shaped elevations in a graph that plots the number of similar sequences at each residue of a query sequence. We used our program to quantitatively corroborate the premise that segments with conserved sequences correspond to domains that fold into native structures. We applied our program to a test data set composed of 99 amino acid sequences containing 150 segments with structures listed in the Protein Data Bank, and thus known to fold into native structures. Overall, the fragments identified by our program have an almost 50% probability of forming a native structure, and comparable results are observed with sequences containing domain linkers classified in SCOP. Furthermore, we verified that our program identifies AFU in libraries from various organisms, and we found a significant number of AFU candidates for structural analysis, covering an estimated 5 to 20% of the genomic databases. Altogether, these results argue that methods based on sequence similarity can be useful for dissecting large proteins into small autonomously folding domains, and such methods may provide an efficient support to structural genomics projects.

Algorithms↗
PubMed2001

Protein structure prediction and structural genomics.

Genome sequencing projects are producing linear amino acid sequences, but full understanding of the biological role of these proteins will require knowledge of their structure and function. Although experimental structure determination methods are providing high-resolution structure information about a subset of the proteins, computational structure prediction methods will provide valuable information for the large fraction of sequences whose structures will not be determined experimentally. The first class of protein structure prediction methods, including threading and comparative modeling, rely on detectable similarity spanning most of the modeled sequence and at least one known structure. The second class of methods, de novo or ab initio methods, predict the structure from sequence alone, without relying on similarity at the fold level between the modeled sequence and any of the known structures. In this Viewpoint, we begin by describing the essential features of the methods, the accuracy of the models, and their application to the prediction and understanding of protein function, both for single proteins and on the scale of whole genomes. We then discuss the important role that protein structure prediction methods play in the growing worldwide effort in structural genomics.

Amino Acid Sequence↗