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PubMed2001

Highly sensitive and selective fluorescence assays for rapid screening of endothelin-converting enzyme inhibitors.

The highly potent vasoconstrictor peptide endothelin (ET) is generated from an inactive precursor, big endothelin (bET), by endothelin-converting enzyme (ECE). ECE is a phosphoramidon-sensitive zinc metallopeptidase, which is closely related to neprilysin (neutral endopeptidase). It is possible that compounds which inhibit the formation of ET may be used as new drugs for the treatment of cardiovascular diseases. Such an approach requires a fast, simple and selective assay to measure ECE activity, allowing rapid screening of inhibitors. We describe here two new ECE substrates based on the concept of 'intramolecularly quenched fluorescence' which may fulfill this aim. One, S(1) [Pya(21)-Nop(22)-bET-1(19--35)], is the (19--35) fragment of the natural peptide big-ET-1(1--38), which is modified by introducing the fluorescent amino acid, pyrenylalanine (Pya), in position 21 and a quencher, p-nitrophenylalanine (Nop), in position 22. The second substrate (S(2)) is a small peptide, Ac-Ser-Gly-Pya-Lys-Ala-Phe-Ala-Nop-Gly-Lys-NH(2), from a biased substrate peptide library. The recombinant, hECE-1c, cleaved both Pya(21)-Nop(22)-bET-1(19--35) and the natural substrate selectively between residues 21 and 22, whereas cleavage occurred between alanine and phenylalanine in the small peptide. In both cases, this generated intense fluorescence emission. The synthesis and kinetic parameters of these substrates are described. These assays, which can be used directly on tissue homogenates, are the most sensitive and selective described to date for ECE, and are easily automated for a high-throughput screening of inhibitors.

Amino Acid Sequence↗
PubMed1995

Peptide binding specificity of HLA-DR4 molecules: correlation with rheumatoid arthritis association.

We have investigated whether sequence 67 to 74 shared by beta chains of rheumatoid arthritis (RA)-associated HLA-DR molecules imparts a specific pattern of peptide binding. The peptide binding specificity of the RA-associated molecules, DRB1*0401, DRB1*0404, and the closely related, RA nonassociated DRB1*0402 was, therefore, determined using designer peptide libraries. The effect of single key residues was tested with site-directed mutants of DRB1*0401. The results have demonstrated striking differences between RA-linked and unlinked DR allotypes in selecting the portion of peptides that interacts with the 67-74 area. Most differences were associated with a single amino acid exchange at position 71 of the DR beta chain, and affected the charge of residues potentially contacting position 71. The observed binding patterns permitted an accurate prediction of natural protein derived peptide sequences that bind selectively to RA-associated DR molecules. Thus, the 67-74 region, in particular position 71, induces changes of binding specificity that correlate with the genetic linkage of RA susceptibility. These findings should facilitate the identification of autoantigenic peptides involved in the pathogenesis of RA.

Amino Acid Sequence↗
PubMedDate not supplied

Development of a new treatment for Alzheimer's disease and Parkinson's disease using anti-aggregatory beta-synuclein-derived peptides.

The synaptic protein alpha-synuclein is a major constituent of Lewy bodies (LB), pathological neuronal inclusion bodies found in Parkinson's disease (PD), Alzheimer's disease (AD), and other neurodegenerative disorders. Owing to data from patient brains, it was speculated that an imbalance between alpha-synuclein and beta-synuclein might be one of the reasons for formation of LBs and the consequent functional deficits. This was supported by the fact that beta-synuclein is able to prevent abnormal alpha-synuclein aggregation. Transgenic mice overexpressing alpha-synuclein display LB-like inclusions in different brain regions and motor deficits. To verify if re-establishing a normal relation between alpha-synuclein and beta-synuclein is able to prevent the pathology, bigenic mice have been created that overexpress both synucleins. Beta-synuclein decreased formation of LBs by 40% and prevented functional deficits. This is considered as preliminary in vivo proof of antiaggregatory function of beta-synuclein and its potential as therapeutic substance for treatment of neurodegenerative disorders linked with abnormal protein aggregation. Peptide libraries have been synthesized to explore the active structures of beta-synuclein. The first 15 N-terminal amino-acids turned out to be important for the antiaggregatory effect. Further smaller beta-synuclein-derived peptides have screened for antiaggregatory and neuroprotective potency in different tissue-culture systems. Preliminary data suggest some of them can be used as leads for further drug development.

Alzheimer Disease↗
PubMed1997

Peptide synthesis on Sepharose beads.

NHS-activated Pharmacia HiTrap Sepharose was modified with 1, 3-diaminopropane to give an amino-functionalized support suitable for solid-phase peptide synthesis. The amide linker p-[(R1S)-alpha-[1-(9H-fluoren-9-yl)-methoxyformamido]- 2, 4-dimethoxybenzyl]phenoxyacetic acid was incorporated and the acyl carrier protein sequence 65-74 was synthesized manually on this support by the Fmoc procedure under controlled conditions with monitoring of the coupling reactions. The performance of the support in automated multiple synthesis in open reactors, with an Abimed AMS 422 according to standard protocols, was evaluated by the synthesis of the acyl carrier protein sequence 65-74 and two other 15-mer and 18-mer peptides. The quality of the resulting crude peptides was determined by HPLC and MALDI-MS, and compared with the same sequences synthesized in parallel on the commercial peptide synthesis resin TentaGel S RAM. The modified HiTrap material was found to be particularly suited for Fmoc solid-phase peptide synthesis and should be advantageous for the utilization of immobilized peptides and peptide libraries in biological assays.

Acyl Carrier Protein↗
PubMed2005

Classification of A1- and A24-supertype molecules by analysis of their MHC-peptide binding repertoires.

At the functional level, the majority of human leukocyte antigen (HLA) class I MHC variants can be classified into about ten different major groups, or supertypes, characterized by overlapping peptide binding motifs and repertoires. Previous studies have detailed the peptide binding specificity of the HLA A2, A3, B7, and B44 supertypes, and predicted, on the basis of MHC pocket structures, known motifs, or the sequence of T cell epitopes, the existence of the HLA A1 and A24 supertypes. Direct experimental validation of the A1 and A24 supertypes, however, has been lacking. In the current study, the peptide-binding repertoires and main anchor specificities of several common HLA A molecules (A*0101, A*2301, A*2402, A*2601, A*2902, and A*3002) predicted to be members of the A1 or A24 supertypes were analyzed and defined using single amino acid substituted peptides and a large peptide library. Based on the present findings, the A1 supertype includes A*0101, A*2601, A*2902, and A*3002, whereas the A24 supertype includes A*2301 and A*2402. Interestingly, A*2902 is associated with a motif and peptide binding repertoire that overlaps significantly with those of all of the A1- and A24-supertype molecules studied, representing-to our knowledge-the first report of significant cross-reactivity among molecules belonging to different supertypes.

Amino Acid Motifs↗
PubMed2005

C-terminal recognition by 14-3-3 proteins for surface expression of membrane receptors.

Diverse functions of 14-3-3 proteins are directly coupled to their ability to interact with targeted peptide substrates. RSX(pS/pT)XP and RXPhiX(pS/pT)XP are two canonical consensus binding motifs for 14-3-3 proteins representing the two common binding modes, modes I and II, between 14-3-3 and internal peptides. Using a genetic selection, we have screened a random peptide library and identified a group of C-terminal motifs, termed SWTY, capable of overriding an endoplasmic reticulum localization signal and redirecting membrane proteins to cell surface. Here we report that the C-terminal SWTY motif, although different from mode I and II consensus, binds tightly to 14-3-3 proteins with a dissociation constant (K(D)) of 0.17 microM, comparable with that of internal canonical binding peptides. We show that all residues but proline in -SWTX-COOH are compatible for the interaction and surface expression. Because SWTY-like sequences have been found in native proteins, these results support a broad significance of 14-3-3 interaction with protein C termini. The C-terminal binding consensus, mode III, represents an expansion of the repertoire of 14-3-3-targeted sequences.

14-3-3 Proteins↗
PubMed1999

Structural and functional characterization of an epitope in the conserved C-terminal region of HIV-1 gp120.

Through an integrated study of the reactivity of a monoclonal antibody, 803-15.6, with synthetic peptides and native recombinant HIV-1 envelope glycoprotein gp120, we have obtained structure-functional information on a region of rgp120 not yet elucidated by X-ray crystallography. mAb 803-15.6 binds with high affinity and broad cross-clade specificity to the conserved C-terminal region (amino acids 502-516) of HIV-1 rgp120. Phage display selection from a random peptide library identified the core binding motif as AXXKXRH, homologous to residues 502-508. Using quantitative binding analyses, the affinity of mAb 803-15.6 for native, monomeric recombinant gp120HXB2 (rgp120) was found to be similar to that for the synthetic gp120 peptide (502-516). Circular dichroism studies indicate that the synthetic peptide largely has a random coil conformation in solution. The results therefore suggest that the 803-15.6 epitope is fully accessible on rgp120 and that this region of rgp120 is as flexible as the synthetic peptide. Residues 502-504 are on the edge of a putative gp41 binding site that has been postulated to change conformation on CD4 binding. However, the affinity of mAb 803-15.6 for rgp120 is not affected by binding of CD4 and vice-versa. These results suggest either that the 502-504 region does not change conformation upon CD4 binding, or that recombinant gp120 does not undergo the same changes as occur in the native viral gp120-gp41 oligomer. The detailed characterization of the 803-15.6 epitope may be useful for further study of the role of the C5 region of gp120 in the viral attachment and fusion process.

Amino Acid Sequence↗
PubMed2004

Identification of an inhibitor-binding site to HIV-1 integrase with affinity acetylation and mass spectrometry.

We report a methodology that combines affinity acetylation with MS analysis for accurate mapping of an inhibitor-binding site to a target protein. For this purpose, we used a known HIV-1 integrase inhibitor containing aryl di-O-acetyl groups (Acetylated-Inhibitor). In addition, we designed a control compound (Acetylated-Control) that also contained an aryl di-O-acetyl group but did not inhibit HIV-1 integrase. Examination of the reactivity of these compounds with a model peptide library, which collectively contained all 20 natural amino acids, revealed that aryl di-O-acetyl compounds effectively acetylate Cys, Lys, and Tyr residues. Acetylated-Inhibitor and Acetylated-Control exhibited comparable chemical reactivity with respect to these small peptides. However, these two compounds differed markedly in their interactions with HIV-1 integrase. In particular, Acetylated-Inhibitor specifically acetylated K173 at its inhibitory concentration (3 microM) whereas this site remained unrecognized by Acetylated-Control. Our data enabled creation of a detailed model for the integrase:Acetylated-Inhibitor complex, which indicated that the inhibitor selectively binds at an architecturally critical region of the protein. The methodology reported herein has a generic application for systems involving a variety of ligand-protein interactions.

Acetylation↗
PubMed1997

Green fluorescent protein as a signal for protein-protein interactions.

Green fluorescent protein (GFP) is autofluorescent. This property has made GFP useful in monitoring in vivo activities such as gene expression and protein localization. We find that GFP can be used in vitro to reveal and characterize protein-protein interactions. The interaction between the S-peptide and S-protein fragments of ribonuclease A was chosen as a model system. GFP-tagged S-peptide was produced, and the interaction of this fusion protein with S-protein was analyzed by two distinct methods: fluorescence gel retardation and fluorescence polarization. The fluorescence gel retardation assay is a rapid method to demonstrate the existence of a protein-protein interaction and to estimate the dissociation constant (Kd) of the resulting complex. The fluorescence polarization assay is an accurate method to evaluate Kd in a specified homogeneous solution and can be adapted for the high-throughput screening of protein or peptide libraries. These two methods are powerful new tools to probe protein-protein interactions.

Fluorescence Polarization↗
PubMed2001

A high-throughput screen for identifying transmembrane pore-forming peptides.

We have developed a visual microwell plate assay for rapid, high-throughput screening for membrane-disrupting molecules such as de novo designed pore formers, antibiotic peptides, bacterial toxins, and lipases. The detectability is based on the strong fluorescence emission of the lanthanide metal terbium(III) (Tb(3+)) when it interacts with the aromatic chelator dipicolinic acid (DPA). While Tb(3+) is not strongly fluorescent alone, the binary complex emits bright green fluorescence when irradiated with uv light. For the microwell plate assay, we prepared unilamellar phospholipid vesicles that had either Tb(3+) or DPA entrapped and the opposite molecule in the external solution. Disruption of the membranes allows the Tb(3+)/DPA complex to form, giving rise to a visibly fluorescent solution. In plates with 20-microl wells, the lower limit of visual detectability of the Tb(3+)/DPA complex in solution was about 2.5 microM. The lower limit of detectability using vesicles with entrapped Tb(3+) or DPA was about 50 microM phospholipid. We show that the membrane-disrupting effect of as little as 0.25 microM or 5 pmol of the pore-forming, antibiotic peptide alamethicin can be detected visually with this system. This sensitive, high-throughput assay is readily automatable and makes possible the visual screening of combinatorial peptide libraries for members that permeabilize lipid bilayer membranes.

Alamethicin↗
PubMed2002

Scavenger receptor block as strategy for the identification of bone marrow homing phages by panning in vivo random peptide phage displayed libraries.

Surface molecules exclusively expressed by cells of the bone marrow (BM) are candidate targets for delivering therapeutic agents to this tissue. To identify ligands specific for the BM, we performed a series of pannings in vivo with random peptide phage displayed libraries (RPPDL). We could show that phages bind to bone marrow endothelium (BME) independently of the peptide insert, suggesting that the BM, similarly to spleen and liver, is part of the reticulo-endothelial system (RES). Furthermore, this strong "natural" affinity to the BME was abrogated by polyanions, indicating that phage trapping by this endothelium is mediated by scavenger receptors (SR). To circumvent interference by SR, polyinosinic acid was administered before phage panning in vivo. This led to the identification of a consensus motif that confers binding specificity for a subpopulation of hemopoietic marrow cells. Thus, SR inhibition, by avoiding phage trapping by the endothelium, seems to allow phage particles to extravasate and reach parenchymal cells. Accordingly, this panning strategy in vivo may be useful for the identification of targeting motifs specific for cells located in the extravascular space of various tissues.

Amino Acid Motifs↗
PubMed2005

Toward a better understanding of the basis of the molecular mimicry of polysaccharide antigens by peptides: the example of Shigella flexneri 5a.

Protein conjugates of oligosaccharides or peptides that mimic complex bacterial polysaccharide antigens represent alternatives to the classical polysaccharide-based conjugate vaccines developed so far. Hence, a better understanding of the molecular basis ensuring appropriate mimicry is required in order to design efficient carbohydrate mimic-based vaccines. This study focuses on the following two unrelated sets of mimics of the Shigella flexneri 5a O-specific polysaccharide (O-SP): (i) a synthetic branched pentasaccharide known to mimic the average solution conformation of S. flexneri 5a O-SP, and (ii) three nonapeptides selected upon screening of phage-displayed peptide libraries with two protective murine monoclonal antibodies (mAbs) of the A isotype specific for S. flexneri 5a O-SP. By inducing anti-O-SP antibodies upon immunization in mice when appropriately presented to the immune system, the pentasaccharide and peptides p100c and p115, but not peptide p22, were qualified as mimotopes of the native antigen. NMR studies based on transferred NOE (trNOE) experiments revealed that both kinds of mimotopes had an average conformation when bound to the mAbs that was close to that of their free form. Most interestingly, saturation transfer difference (STD) experiments showed that the characteristic turn conformations adopted by the major conformers of p100c and p115, as well as of p22, are clearly involved in mAb binding. These latter experiments also showed that the branched glucose residue of the pentasaccharide was a key part of the determinant recognized by the protective mAbs. Finally, by using NMR-derived pentasaccharide and peptide conformations coupled to STD information, models of antigen-antibody interaction were obtained. Most interestingly, only one model was found compatible with experimental data when large O-SP fragments were docked into one of the mIgA-binding sites. This newly made available system provides a new contribution to the understanding of the molecular mimicry of complex polysaccharides by peptides and short oligosaccharides.

Amino Acid Sequence↗
PubMed2006

Sequence specificity of SHP-1 and SHP-2 Src homology 2 domains. Critical roles of residues beyond the pY+3 position.

A combinatorial phosphotyrosyl (pY) peptide library was screened to determine the amino acid preferences at the pY+4 to pY+6 positions for the four SH2 domains of protein-tyrosine phosphatases SHP-1 and SHP-2. Individual binding sequences selected from the library were resynthesized and their binding affinities and specificities to various SH2 domains were further evaluated by SPR studies, stimulation of SHP-1 and SHP-2 phosphatase activity, and in vitro pulldown assays. These studies reveal that binding of a pY peptide to the N-SH2 domain of SHP-2 is greatly enhanced by a large hydrophobic residue (Trp, Tyr, Met, or Phe) at the pY+4 and/or pY+5 positions, whereas binding to SHP-1 N-SH2 domain is enhanced by either hydrophobic or positively charged residues (Arg, Lys, or His) at these positions. Similar residues at the pY+4 to pY+6 positions are also preferred by SHP-1 and SHP-2 C-SH2 domains, although their influence on the overall binding affinities is much smaller compared with the N-SH2 domains. A structural model was generated to qualitatively interpret the contribution of the pY+4 and pY+5 residues to the overall binding affinity. Examination of pY motifs from known SHP-1 and SHP-2-binding proteins shows that many of the pY motifs contain a hydrophobic or positively charged residue(s) at the pY+4 and pY+5 positions.

Amino Acid Sequence↗
PubMedDate not supplied

Characterization of recombinant shrimp allergen Pen a 1 (tropomyosin).

Tropomyosin (Pen a 1) from brown shrimp, Penaeus aztecus, has been identified as the only major shrimp allergen. Since beef, pork and chicken are other tropomyosin-containing foods that are not very allergenic, tropomyosins can serve to investigate the contribution of the structural properties of a protein to its allergenicity. The aim of this study was to determine the primary structure of Pen a 1 and to identify IgE-binding epitopes. The screening of a unidirectional expression cDNA library from shrimp tail muscle with the Pen-a-1-specific monoclonal antibody 4.9.5 resulted in 4 positive Escherichia coli clones. Immunoblot analysis with human sera from shrimp-allergic subjects demonstrated IgE binding of all 4 recombinant shrimp proteins. Three of 4 expressed recombinant proteins have a molecular weight of approximately 36 kD, consistent with the molecular weight of natural Pen a 1. The DNA sequence analysis identified these recombinant shrimp proteins as tropomyosin and could be aligned with the sequence of greasyback shrimp (Metapenaeus ensis) tropomyosin (Met e 1). In order to characterize contiguous IgE-binding epitopes of Pen a 1, a peptide library (Novagen epitope mapping system) expressing 10-30 amino-acid-residue-long recombinant Pen a 1 peptides was constructed and screened with human IgE. Four recombinant, IgE-reactive Pen a 1 peptides were selected and sequenced. They show various degrees of sequence identity with tropomyosins of other arthropods, such as fruitfly and house dust mite, helminths and vertebrates.

Allergens↗
PubMed2002

Gliadin T cell epitope selection by tissue transglutaminase in celiac disease. Role of enzyme specificity and pH influence on the transamidation versus deamidation process.

Tissue transglutaminase (TG2) can modify proteins by transamidation or deamidation of specific glutamine residues. TG2 has a major role in the pathogenesis of celiac disease as it is both the target of disease-specific autoantibodies and generates deamidated gliadin peptides that are recognized by CD4(+), DQ2-restricted T cells from the celiac lesions. Capillary electrophoresis with fluorescence-labeled gliadin peptides was used to separate and quantify deamidated and transamidated products. In a competition assay, the affinity of TG2 to a set of overlapping gamma-gliadin peptides was measured and compared with their recognition by celiac lesion T cells. Peptides differed considerably in their competition efficiency. Those peptides recognized by intestinal T cell lines showed marked competition indicating them as excellent substrates for TG2. The enzyme fine specificity of TG2 was characterized by synthetic peptide libraries and mass spectrometry. Residues in positions -1, +1, +2, and +3 relative to the targeted glutamine residue influenced the enzyme activity, and proline in position +2 had a particularly positive effect. The characterized sequence specificity of TG2 explained the variation between peptides as TG2 substrates indicating that the enzyme is involved in the selection of gluten T cell epitopes. The enzyme is mainly localized extracellularly in the small intestine where primary amines as substrates for the competing transamidation reaction are present. The deamidation could possibly take place in this compartment as an excess of primary amines did not completely inhibit deamidation of gluten peptides at pH 7.3. However, lowering of the pH decreased the reaction rate of the TG2-catalyzed transamidation, whereas the rate of the deamidation reaction was considerably increased. This suggests that the deamidation of gluten peptides by TG2 more likely takes place in slightly acidic environments.

Amino Acid Sequence↗
PubMed2026

Peptide ligands targeting GP64 for the purification of Baculovirus from insect cell lysates.

Autographa californica multiple nucleopolyhedrovirus, known as Baculovirus, is a widely used platform for producing therapeutic proteins and viral vectors. The purity and infectious activity of Baculovirus stocks determine the quality and productivity of recombinant products produced through this system. Current purification strategies suffer from major limitations: centrifugation lacks productivity and scalability; ion-exchange chromatography affords limited selectivity and purity; and the only commercial affinity resin requires harsh elution conditions that significantly reduce functional product recovery. To overcome these limitations, this study introduces the first peptide affinity ligands targeting the baculoviral envelope glycoprotein GP64 for the purification of active Baculovirus particles. We implemented a combinatorial selection workflow based on dual-fluorescence screening of solid-phase peptide libraries to identify 12-mer sequences that bind GP64 and elute Baculovirus under mild conditions (pH 8.5). As the selected ligands are enriched in histidine and tyrosine residues, product release is effected by the combined modulation of pH and ionic strength. Eight candidate peptides (SB1-SB8) were evaluated on Toyopearl and POROS chromatographic resins, demonstrating that matrix chemistry, pore size, and ligand density govern purification performance. The lead peptide SB4 conjugated to POROS resin at ∼10 µmol/mL achieved 81% recovery of infectious virions (transducing units), robust host cell protein reduction (LRV 1.65), and a dynamic binding capacity (DBC10%) of 1.9 × 1010 vg/mL resin. Transmission electron microscopy and multi-angle light scattering confirmed the integrity of purified particles (200 × 50 nm rods with intact nucleocapsids), compared to BacuClear eluates that showed collapsed morphology. The SB4-POROS resin demonstrated storage stability and ∼80% retention of binding capacity over ten purification-regeneration cycles with caustic cleaning. Integration into a three-step downstream process (clarification, affinity capture, and polishing) raised product purity 1,528-fold, from 6.22 × 106 to 9.50 × 109 viral genomes per µg of HCP, while reducing the total HCP burden 1,698-fold, at a cumulative transducing-unit yield of ∼69% relative to the feedstock, establishing SB4-POROS as a promising technology with a favorable projected cost structure for Baculovirus purification.

Affinity chromatography↗
PubMed2005

Identification and characterization of peptides mimicking the epitopes of metalloprotease of Schistosoma japonicum.

In an attempt to isolate and characterize peptides mimicking epitopes of metalloprotease and explore their immunological protection against Schistosoma japonicum (S. japonicum), polyclonal anti-metalloprotease sera was prepared to screen a 12-mer random peptide library to isolate phages binding specially to antisera IgG. Then, phage ELISA, animal immunization, DNA sequencing, Western blotting and enzymatic activity neutralizing analysis were used to characterize the selected phage clones. All of ten randomly picked clones were shown to be positive. Five peptides of different amino acid sequences deduced from DNA sequences were obtained and two of them (peptides 2 and 3) could induce significant reduction (31.0% and 31.8%, respectively) in worm burden and high reduction (52.6% and 54.9%, respectively) in liver eggs per gram (LEPG), while, unexpectedly, others (peptides 1, 4 and 5) could not elicit enough protection against infection of S. japonicum. Peptides 2 and 3 could be recognized by S. japonicum infected mouse sera (IMS) and could elicit neutralizing Abs. The results show that peptides 2 and 3 are antigenic and immunogenic. They are true mimics of epitopes of metalloprotease and useful as novel vaccine candidates against S. japonicum.

Amino Acid Sequence↗
PubMed2003

Differential receptors create patterns diagnostic for ATP and GTP.

Herein we report the combination of a library of resin-bound sensors along with a multicomponent sensor array. This novel combinatorial array sensor system shows selectivity for nucleotide phosphates in solution. The design of the anchored receptor includes a 1,3,5-trisubstituted-2,4,6-triethylbenzene scaffold coupled with peptide libraries. Each chemosensor is placed into a micromachined cavity within a silicon wafer, and the optical changes observed by a charged-coupled device result in near-real-time digital analysis of solutions. A colorimetric displacement assay was performed, and time-dependent imaging studies of the selected sensing ensembles result in a differential responses upon addition of adenosine 5'-triphosphate (ATP), adenosine 5'-monophosphate (AMP), or guanosine 5'-triphosphate (GTP). An advantage to this approach is that it creates an array of sensors that gives a fingerprint response for each analyte. Principal component analysis indicates that the library of chemosensors can differentiate between ATP, GTP, and AMP. On the basis of factor loading values, individual sensors from the library were sequenced to elucidate their chemical composition.

Adenosine Triphosphate↗