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PubMed1993

Mapping the surface properties of macromolecules.

Methods are presented for the rapid computation of schematic projections of the surfaces of macromolecules, similar to the "roadmaps" used to illustrate the surfaces of viruses (Rossmann, M.G. & Palmenberg, A.C., 1988, Virology 164, 373-382). Several types of projections are described, extending the application of "roadmaps" to the external surfaces of all macromolecules and their interior binding pockets and pores. The surface projections, showing the positions of residues, can be colored, shaded, contoured, and annotated to show physical, sequence, or functional properties such as surface topology, hydrophobicity, or sequence conservation, for example. The automated procedures are useful for surveys of the surface features of proteins sharing similar functional properties.

Computer Graphics↗

PubMedDate not supplied

The ABC of ABCS: a phylogenetic and functional classification of ABC systems in living organisms.

ATP binding cassette (ABC) systems constitute one of the most abundant superfamilies of proteins. They are involved not only in the transport of a wide variety of substances, but also in many cellular processes and in their regulation. In this paper, we made a comparative analysis of the properties of ABC systems and we provide a phylogenetic and functional classification. This analysis will be helpful to accurately annotate ABC systems discovered during the sequencing of the genome of living organisms and to identify the partners of the ABC ATPases.

ATP-Binding Cassette Transporters↗

PubMed2006

Genomic fossils as a snapshot of the human transcriptome.

Processed pseudogenes (PPGs) are cDNA sequences that were generated through reverse transcription of mature, spliced mRNAs and have subsequently been reinserted at a new genomic location. These cDNA sequences are usually no longer transcribed and are considered "dead on arrival." Here we show that PPGs can be used to generate a map of the transcriptome. By analyzing thousands of human PPGs, we were able to discover hundreds of transcript variants so far unidentified. An experimental verification of a subset of these variants by RT-PCR indicates that most of them are still active in the human transcriptome. Furthermore, we demonstrate that PPGs can enable the identification of ancient splice variants that were expressed ancestrally but are now extinct. Our results show that the genome itself carries a "virtual cDNA library" that can readily be used to analyze both present and ancestral transcripts. Our approach can be applied to sequenced metazoan genomes to computationally annotate splicing variation even when expressed sequences are unavailable.

Alternative Splicing↗

PubMed2002

Full subunit coverage liquid chromatography electrospray ionization mass spectrometry (LCMS+) of an oligomeric membrane protein: cytochrome b(6)f complex from spinach and the cyanobacterium Mastigocladus laminosus.

Highly active cytochrome b(6)f complexes from spinach and the cyanobacterium Mastigocladus laminosus have been analyzed by liquid chromatography with electrospray ionization mass spectrometry (LCMS+). Both size-exclusion and reverse-phase separations were used to separate protein subunits allowing measurement of their molecular masses to an accuracy exceeding 0.01% (+/-3 Da at 30,000 Da). The products of petA, petB, petC, petD, petG, petL, petM, and petN were detected in complexes from both spinach and M. laminosus, while the spinach complex also contained ferredoxin-NADP(+) oxidoreductase (Zhang, H., Whitelegge, J. P., and Cramer, W. A. (2001) Flavonucleotide:ferredoxin reductase is a subunit of the plant cytochrome b(6)f complex. J. Biol. Chem. 276, 38159-38165). While the measured masses of PetC and PetD (18935.8 and 17311.8 Da, respectively) from spinach are consistent with the published primary structure, the measured masses of cytochrome f (31934.7 Da, PetA) and cytochrome b (24886.9 Da, PetB) modestly deviate from values calculated based upon genomic sequence and known post-translational modifications. The low molecular weight protein subunits have been sequenced using tandem mass spectrometry (MSMS) without prior cleavage. Sequences derived from the MSMS spectra of these intact membrane proteins in the range of 3.2-4.2 kDa were compared with translations of genomic DNA sequence where available. Products of the spinach chloroplast genome, PetG, PetL, and PetN, all retained their initiating formylmethionine, while the nuclear encoded PetM was cleaved after import from the cytoplasm. While the sequences of PetG and PetN revealed no discrepancy with translations of the spinach chloroplast genome, Phe was detected at position 2 of PetL. The spinach chloroplast genome reports a codon for Ser at position 2 implying the presence of a DNA sequencing error or a previously undiscovered RNA editing event. Clearly, complete annotation of genomic data requires detailed expression measurements of primary structure by mass spectrometry. Full subunit coverage of an oligomeric intrinsic membrane protein complex by LCMS+ presents a new facet to intact mass proteomics.

Amino Acid Sequence↗

PubMed2026

'PePApipe': A complete bioinformatics analysis pipeline for African Swine Fever Virus genome.

African Swine Fever Virus (ASFV) is of high concern in porcine livestock across the world due to both the high mortality rates and the trade restrictions imposed on affected regions. The viral genome is large and complex, and genomic analysis is essential for tracing its origin and evolution. Although several bioinformatics tools exist for genome assembly and analysis, no single platform integrates all necessary steps in an accessible and systematic way. In this study the authors developed 'PePApipe', a custom-built, user-friendly pipeline that enables rapid, complete, and efficient ASFV genome analysis. It is specifically designed for laboratory professionals with limited bioinformatics experience, requiring only basic command-line knowledge. Starting from raw sequencing data, PePApipe integrates thirteen software tools into one automated workflow, covering quality control and pre-processing of raw reads, de novo genome assembly and variant calling. Programmed in Python, it can be executed locally through bash scripts, or using a Slurm protocol for batch processing of multiple samples. The main outputs are the ASFV consensus genome sequence and a file listing its putative variants compared to the selected reference genome. PePApipe classifies generated files into structured folders and produces intermediate files that can be used as inputs for further or parallel analyses; users can also enable or disable specific steps in each particular case. This pipeline is adaptable and complementary to downstream steps such as viral genome annotation or genome visualization. By consolidating all stages of viral genome analysis into a single automated workflow, PePApipe reduces the likelihood of user error, and enhances reproducibility and efficiency. This user-friendly pipeline facilitates the transition from sequencing to assembly and downstream analysis of viral genomes, ensuring a fast and reliable response to molecular analysis demands. Finally, the pipeline can be easily adapted to the study of other viral species, expanding its application in infectious diseases surveillance.

African Swine Fever Virus↗

PubMed2004

New approaches towards integrated proteomic databases and depositories.

Since the publication of the human genome, two key points have emerged. First, it is still not certain which regions of the genome code for proteins. Second, the number of discrete protein-coding genes is far fewer than the number of different proteins. Proteomics has the potential to address some of these postgenomic issues if the obstacles that we face can be overcome in our efforts to combine proteomic and genomic data. There are many challenges associated with high-throughput and high-output proteomic technologies. Consequently, for proteomics to continue at its current growth rate, new approaches must be developed to ease data management and data mining. Initiatives have been launched to develop standard data formats for exchanging mass spectrometry proteomic data, including the Proteomics Standards Initiative formed by the Human Proteome Organization. Databases such as SwissProt and Uniprot are publicly available repositories for protein sequences annotated for function, subcellular location and known potential post-translational modifications. The availability of bioinformatics solutions is crucial for proteomics technologies to fulfil their promise of adding further definition to the functional output of the human genome. The aim of the Oxford Genome Anatomy Project is to provide a framework for integrating molecular, cellular, phenotypic and clinical information with experimental genetic and proteomics data. This perspective also discusses models to make the Oxford Genome Anatomy Project accessible and beneficial for academic and commercial research and development.

Databases, Protein↗

PubMed1993

Building large knowledge bases in molecular biology.

Large scale genome sequencing projects are now producing hugh amounts of data which can be readily stored and managed within data base management systems, and analyzed using dedicated software packages. The results of these analyzes should also be stored with the input DNA sequences. The increasing complexity and size of the objects to be described and managed have led biologists to rely on advanced data models such as the object-oriented model. As a joint effort between our computer science and molecular biology research projects, the knowledge bases we have developed in molecular genetics have shown however that the basic object-oriented model is not fully adapted to the complexity of some biological situations encountered. Advanced descriptive capabilities, provided only by knowledge models originated from the AI field, are required. Composite or evolving objects, multiple viewpoints, constraints, tasks and methods, textual annotations are some examples of such capabilities. They are illustrated by biological situations for which they appeared to be necessary. Supporting powerful reasoning mechanisms (e.g. object classification, constraint propagation or qualitative simulators), they allow the development of large knowledge bases in molecular biology. These knowledge bases are expected to become the adequate support for co-operative distributed research efforts.

Artificial Intelligence↗

PubMed2005

Protein variety and functional diversity: Swiss-Prot annotation in its biological context.

We all know that the dogma 'one gene, one protein' is obsolete. A functional protein and, likewise, a protein's ultimate function depend not only on the underlying genetic information but also on the ongoing conditions of the cellular system. Frequently the transcript, like the polypeptide, is processed in multiple ways, but only one or a few out of a multitude of possible variants are produced at a time. An overview on processes that can lead to sequence variety and structural diversity in eukaryotes is given. The UniProtKB/Swiss-Prot protein knowledgebase provides a wealth of information regarding protein variety, function and associated disorders. Examples for such annotation are shown and further ones are available at http://www.expasy.org/sprot/tutorial/examples_CRB.

Amino Acid Sequence↗

PubMed2005

Community-based gene structure annotation.

Uncertainty and inconsistency of gene structure annotation remain limitations on research in the genome era, frustrating both biologists and bioinformaticians, who have to sort out annotation errors for their genes of interest or to generate trustworthy datasets for algorithmic development. It is unrealistic to hope for better software solutions in the near future that would solve all the problems. The issue is all the more urgent with more species being sequenced and analyzed by comparative genomics - erroneous annotations could easily propagate, whereas correct annotations in one species will greatly facilitate annotation of novel genomes. We propose a dynamic, economically feasible solution to the annotation predicament: broad-based, web-technology-enabled community annotation, a prototype of which is now in use for Arabidopsis.

Arabidopsis↗

PubMedDate not supplied

Novel intergenic repeats of Escherichia coli K-12.

An online catalog of intergenic DNA repeat sequence elements is added to the EcoGene Escherichia coli K-12 genome sequence annotation and analysis project (bmb.med.miami.edu/EcoGene). A library of noncoding (intergenic) DNA sequences depleted of known intergenic repeat classes was searched for DNA sequence similarities to identify novel DNA repeat sequence classes.

Base Sequence↗

PubMed2000

The histone database: a comprehensive WWW resource for histones and histone fold-containing proteins.

The Histone Database (HDB) is an annotated and searchable collection of all full-length sequences and structures of histone and non-histone proteins containing the histone fold motif. These sequences are both eukaryotic and archaeal in origin. Several new histone fold-containing proteins have been identified, including Spt7p, and a few false positives have been removed from the earlier version of HDB. Database contents include compilations of post-translational modifications for each of the core and linker histones, as well as genomic information in the form of map loci for the human histone gene complement, with the genetic loci linked to Online Mendelian Inheritance in Man (OMIM). Conflicts between similar sequence entries from a number of source databases are also documented. Newly added to the HDB are multiple sequence alignments in which predicted functions of histone fold amino acid residues are annotated. The database is freely accessible through the WWW at http://genome.nhgri.nih.gov/histones/

Amino Acid Sequence↗

PubMed2005

Pattern similarity study of functional sites in protein sequences: lysozymes and cystatins.

BACKGROUND: Although it is generally agreed that topography is more conserved than sequences, proteins sharing the same fold can have different functions, while there are protein families with low sequence similarity. An alternative method for profile analysis of characteristic conserved positions of the motifs within the 3D structures may be needed for functional annotation of protein sequences. Using the approach of quantitative structure-activity relationships (QSAR), we have proposed a new algorithm for postulating functional mechanisms on the basis of pattern similarity and average of property values of side-chains in segments within sequences. This approach was used to search for functional sites of proteins belonging to the lysozyme and cystatin families. RESULTS: Hydrophobicity and beta-turn propensity of reference segments with 3-7 residues were used for the homology similarity search (HSS) for active sites. Hydrogen bonding was used as the side-chain property for searching the binding sites of lysozymes. The profiles of similarity constants and average values of these parameters as functions of their positions in the sequences could identify both active and substrate binding sites of the lysozyme of Streptomyces coelicolor, which has been reported as a new fold enzyme (Cellosyl). The same approach was successfully applied to cystatins, especially for postulating the mechanisms of amyloidosis of human cystatin C as well as human lysozyme. CONCLUSION: Pattern similarity and average index values of structure-related properties of side chains in short segments of three residues or longer were, for the first time, successfully applied for predicting functional sites in sequences. This new approach may be applicable to studying functional sites in un-annotated proteins, for which complete 3D structures are not yet available.

Amino Acid Sequence↗

PubMed2005

A new family of NAD(P)H-dependent oxidoreductases distinct from conventional Rossmann-fold proteins.

A new family of NAD(P)H-dependent oxidoreductases is now recognized as a protein family distinct from conventional Rossmann-fold proteins. Numerous putative proteins belonging to the family have been annotated as malate dehydrogenase (MDH) or lactate dehydrogenase (LDH) according to the previous classification as type-2 malate/L-lactate dehydrogenases. However, recent biochemical and genetic studies have revealed that the protein family consists of a wide variety of enzymes with unique catalytic activities other than MDH or LDH activity. Based on their sequence homologies and plausible functions, the family proteins can be grouped into eight clades. This classification would be useful for reliable functional annotation of the new family of NAD(P)H-dependent oxidoreductases.

Amino Acid Sequence↗

PubMed2005

Domain rearrangements in protein evolution.

Most eukaryotic proteins are multi-domain proteins that are created from fusions of genes, deletions and internal repetitions. An investigation of such evolutionary events requires a method to find the domain architecture from which each protein originates. Therefore, we defined a novel measure, domain distance, which is calculated as the number of domains that differ between two domain architectures. Using this measure the evolutionary events that distinguish a protein from its closest ancestor have been studied and it was found that indels are more common than internal repetition and that the exchange of a domain is rare. Indels and repetitions are common at both the N and C-terminals while they are rare between domains. The evolution of the majority of multi-domain proteins can be explained by the stepwise insertions of single domains, with the exception of repeats that sometimes are duplicated several domains in tandem. We show that domain distances agree with sequence similarity and semantic similarity based on gene ontology annotations. In addition, we demonstrate the use of the domain distance measure to build evolutionary trees. Finally, the evolution of multi-domain proteins is exemplified by a closer study of the evolution of two protein families, non-receptor tyrosine kinases and RhoGEFs.

Databases, Protein↗

PubMed2005

Unusual usage of AGG and TTG codons in humans and their viruses.

Prior analysis on human protein-coding DNA sequences has identified local base composition as the primary predictor of synonymous codon usage. However, in many organisms, codon usage is influenced by natural selection, particularly for efficient expression of functional gene products. Because viruses are expected to evolve codon usage in the context of their host's molecular machinery, their genomes provide another window into the forces that guide their host's molecular evolution. Factor analysis was performed on codon usage of 16,654 genes annotated in Build 34 of the human genome, and the primary factor was correlated strongly with local base composition. However, two codons, AGG and TTG, rose in frequency as all other C- and G-ending codons decreased in frequency. These two codons were the only C- or G-ending codons with usages that negatively correlated with gene expression. Variation among viruses in codon usage also strongly reflects variation in base composition and, again, AGG and TTG decrease in frequency as all other C- and G-ending codons increase in frequency. It appears that usages of these two codons can not be explained by local compositional biases, implying a more direct role of natural selection on codon usage in humans.

Amino Acids↗

PubMed2006

From genome to proteome: developing expression clone resources for the human genome.

cDNA clones have long been valuable reagents for studying the structure and function of proteins. With recent access to the entire human genome sequence, it has become possible and highly productive to compare the sequences of mRNAs to their genes, in order to validate the sequences and protein-coding annotations of each (1,2). Thus, well-characterized collections of human cDNAs are now playing an essential role in defining the structure and function of human genes and proteins. In this review, we will summarize the major collections of human cDNA clones, discuss some limitations common to most of these collections and describe several noteworthy proteomics applications, focusing on the detection and analysis of protein-protein interactions (PPI). These human cDNA collections contain principally two types of cDNA clones. The largest collections comprise cDNAs with full-length protein coding sequences (FL-CDS). Some but not all of these cDNA clones may represent the entire mRNA sequence, but many are missing considerable non-coding UTR sequence, usually at the 5' end. A second type of cDNA clone, a 'full-ORF' (F-ORF) expression clone, is one where the annotated protein-coding sequence, excised of 5' UTR and 3' UTR sequence, has been transferred to a vector designed to facilitate transfer to other vectors for protein expression.

Cloning, Molecular↗

PubMedDate not supplied

An on-line two-dimensional polyacrylamide gel electrophoresis protein database of adult Drosophila melanogaster.

An annotated two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) protein database of adult Drosophila melanogaster has been constructed, based on the protein patterns of heads, thoraces and abdomens of adult male and female Drosophila melanogaster. About 1200 major protein spots are catalogued. Common proteins, found in all body parts, as well as bodypart- and sex-specifically expressed proteins are reported. Of the major proteins, 91, or 7.5%, are differentially expressed in the two sexes or in different body parts, at least in part reflecting specific functional requirements. At the present time 43 proteins, or about 3.5% of the detected proteins, have been identified. These data can be accessed interactively from our World Wide Web (WWW) server through clickable inline gel images and hypertext links. Identified protein spots are cross-referenced, through hypertext links, to the SWISS-PROT annotated database of protein primary sequences and the Fly-Base database of Drosophila genomic data. Our reference gels can be used to gain immediate access to protein spot identify and to the pattern of differentially expressed proteins in Drosophila melanogaster. The work presented in this article ties together information from protein 2-D PAGE, molecular biology and genetics and offers a uniform way to access this large volume of data.

Abdomen↗

PubMed1997

Computational methods for the identification of genes in vertebrate genomic sequences.

Research into new methods to identify genes in anonymous genomic sequences has been going on for more than 15 years. Over this period of time, the field has evolved from the designing of programs to identify protein coding regions in compact mitochondrial or bacterial genomes, to the challenge of predicting the detailed organization of multi-exon vertebrate genes. The best program currently available perfectly locates more than 80% of the internal coding exons, and only 5% of the predictions do not overlap a real exon. Given such accuracy, computational methods are indeed very useful; however, they do not alleviate the need for experimental validation. If the performances are satisfactory for the identification of the coding moiety of genes (internal coding exons), the determination of the full extent of the transcript (5' and 3' extremities of the gene) and the location of promoter regions are still unreliable. As the human and mouse genome sequencing projects enter a production mode, the fully automated annotation of megabase-long anonymous genomic sequences is the next big challenge in bioinformatics.

Animals↗