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At least 1,009 records · Page 56Linked to original sources
PubMed1994

Sepsis increases production of total secreted proteins, vasoactive intestinal peptide, and peptide YY in isolated rat enterocytes.

The effect of sepsis on the synthesis of endogenous and secretory proteins, including vasoactive intestinal peptide (VIP) and peptide YY (PYY), was determined in enterocytes from jejunum of rats. Sepsis was induced by cecal ligation and puncture (CLP). Control rats were sham-operated. Total endogenous and secreted protein synthesis was assessed in incubated jejunal enterocytes by measuring incorporation of 3H-phenylalanine into protein. Release of VIP and PYY into the medium of incubated enterocytes and cellular levels of the gut peptides were measured by radioimmunoassay. Sixteen hours after CLP, synthesis rates of both endogenous and secreted proteins were increased, and this effect of sepsis was most pronounced in cells from the lower parts of the villi and crypts. Enterocytes from septic rats released more VIP and PYY into the incubation medium, and approximately half of the peptides they released were newly synthesized VIP and PYY. Intracellular levels of VIP and PYY were increased as early as 4 hours after induction of sepsis. Our results suggest that sepsis stimulates the synthesis of endogenous and secretory proteins, including certain gut peptides, in small intestine mucosa. This is consistent with previous observations of increased circulating levels of VIP, PYY and other gastrointestinal hormones during sepsis. The biological significance of increased synthesis of gut peptides and other intestinal proteins during sepsis remains to be determined.

Analysis of Variance↗
PubMed1996

Structure-activity analysis of thanatin, a 21-residue inducible insect defense peptide with sequence homology to frog skin antimicrobial peptides.

Immune challenge to the insect Podisus maculiventris induces synthesis of a 21-residue peptide with sequence homology to frog skin antimicrobial peptides of the brevinin family. The insect and frog peptides have in common a C-terminally located disulfide bridge delineating a cationic loop. The peptide is bactericidal and fungicidal, exhibiting the largest antimicrobial spectrum observed so far for an insect defense peptide. An all-D-enantiomer is nearly inactive against Gram-negative bacteria and some Gram-positive strains but is fully active against fungi and other Gram-positive bacteria, suggesting that more than one mechanism accounts for the antimicrobial activity of this peptide. Studies with truncated synthetic isoforms underline the role of the C-terminal loop and flanking residues for the activity of this molecule for which we propose the name thanatin.

Amino Acid Sequence↗
PubMed2003

Calcitonin receptor-stimulating peptide, a new member of the calcitonin gene-related peptide family. Its isolation from porcine brain, structure, tissue distribution, and biological activity.

We isolated a novel biologically active peptide, designated calcitonin receptor-stimulating peptide (CRSP), from the acid extract of the porcine brain by monitoring cAMP production in the porcine kidney cell line LLC-PK(1). Determination of the amino acid sequence and cDNA analysis encoding a CRSP precursor showed that this peptide has approximately 60% identity in the amino acid sequence with human calcitonin gene-related peptide type-alpha (alphaCGRP), type-beta (betaCGRP), and porcine CGRP. Northern blot analysis and radioimmunoassay demonstrated that CRSP is expressed mainly in the thyroid gland and the central nervous system, in which the calcitonin receptor was abundantly expressed. Synthetic CRSP elicited a potent stimulatory effect on the cAMP production in LLC-PK(1) cells. Although it shows significant sequence similarity with CGRPs, this peptide did not elicit cAMP elevation in cells that endogenously expressed a CGRP receptor or an adrenomedullin receptor or were transfected with either of these recombinant receptors. Administration of CRSP into anesthetized rats did not alter the blood pressure but induced a transient decrease in the plasma calcium concentration. In fact, this peptide potently increased the intracellular cAMP concentration in COS-7 cells that expressed the recombinant calcitonin receptor. These unique properties indicate that CRSP is not a porcine counterpart of betaCGRP and probably elicits its biological effects via the calcitonin receptor.

3T3 Cells↗
PubMed2005

Determination of peptide substrate specificity for mu-calpain by a peptide library-based approach: the importance of primed side interactions.

Calpains are proteases that catalyze the limited cleavage of target proteins in response to Ca(2+) signaling. Because of their involvement in pathological conditions such as post-ischemic injury and Alzheimer and Parkinson disease, calpains form a class of pharmacologically significant targets for inhibition. We have determined the sequence preference for the hydrolysis of peptide substrates of the ubiquitous mu-calpain isoform by a peptide library-based approach using the proteolytic core of mu-calpain (muI-II). The approach, first described by Turk et al. (Turk, B. E., Huang, L. L., Piro, E. T., and Cantley, L. C. (2001) Nat. Biotechnol. 19, 661-667), involved the digestion of an N-terminally acetylated degenerate peptide library in conjunction with Edman sequencing to determine the specificity for residues found at primed positions. The cleavage consensus for these positions was then used to design a second, partially degenerate library, to determine specificity at unprimed positions. We have improved upon the original methodology by using a degenerate peptide dendrimer for determination of specificity at unprimed positions. By using this modified approach, the complete cleavage specificity profile for muI-II was determined for all positions flanking the cleaved peptide. A previously known preference of calpains for hydrophobic amino acids at unprimed positions was confirmed. In addition, a novel residue specificity for primed positions was revealed to highlight the importance of these sites for substrate recognition. The optimal primed site motif (MER) was shown to be capable of directing cleavage to a specific peptide bond. Accordingly, we designed a fluorescent resonance energy transfer-based substrate with optimal cleavage motifs on the primed and non-primed sides (PLFAER). The mu-calpain core shows a far greater turnover rate for our substrate than for those based on the cleavage site of alpha-spectrin or the proteolytic sequence consensus compiled from substrate alignments.

Acetylation↗
PubMed1989

Variable distribution of three molecular forms of peptide histidine isoleucinamide in rat tissues: identification of the large molecular form as peptide histidine valine-(1-42).

We previously isolated three forms of peptide histidine isoleucinamide (PHI) from rat small intestine by chromatography on Fractogel. Rat PHI-(1-27)-NH2 and rat PHI-(1-27)-Gly were identified by microsequence analysis. In the present work the third larger form was purified to homogeneity, being detected by RIA in preliminary steps and by RRA in the last steps. This form could be recognized by a PHI antiserum and an antiserum raised against the synthetic rat PHI-(22-27) fragment C-terminally extended by the connecting peptide linking PHI to vasoactive intestinal peptide (VIP) in their common PHI/VIP precursor, as postulated by the reported cDNA analysis of rat brain mRNA. Sequence analysis and C-terminal hydrolysis by carboxypeptidase-Y identified this large form as peptide histidine valine-(1-42), i.e. rat PHI-(1-27) C-terminally extended by the totality of the connecting peptide except for the terminal dibasic residues. We also documented the coexistence of the three PHI forms in rat brain, rachidian bulb, pituitary, adrenal glands, uterine horns, and stomach. Tissue distribution was highly variable. The classical PHI-(1-27)-NH2 form was best represented in rachidian bulb and somewhat less so in brain and uterine horns. PHI-(1-27)-Gly, while being particularly abundant in the small intestine, was very poorly present in rachidian bulb and uterine horns. Peptide histidine valine-(1-42) was the major form in pituitary and adrenal glands and was also well expressed in uterine horns. The three forms coexisted equally in stomach. This uneven distribution suggests a tissue-specific posttranslational processing of rat prepro-PHI/VIP.

Amino Acid Sequence↗
PubMed2005

Surface behavior and lipid interaction of Alzheimer beta-amyloid peptide 1-42: a membrane-disrupting peptide.

Amyloid aggregates, found in patients that suffer from Alzheimer's disease, are composed of fibril-forming peptides in a beta-sheet conformation. One of the most abundant components in amyloid aggregates is the beta-amyloid peptide 1-42 (Abeta 1-42). Membrane alterations may proceed to cell death by either an oxidative stress mechanism, caused by the peptide and synergized by transition metal ions, or through formation of ion channels by peptide interfacial self-aggregation. Here we demonstrate that Langmuir films of Abeta 1-42, either in pure form or mixed with lipids, develop stable monomolecular arrays with a high surface stability. By using micropipette aspiration technique and confocal microscopy we show that Abeta 1-42 induces a strong membrane destabilization in giant unilamellar vesicles composed of palmitoyloleoyl-phosphatidylcholine, sphingomyelin, and cholesterol, lowering the critical tension of vesicle rupture. Additionally, Abeta 1-42 triggers the induction of a sequential leakage of low- and high-molecular-weight markers trapped inside the giant unilamellar vesicles, but preserving the vesicle shape. Consequently, the Abeta 1-42 sequence confers particular molecular properties to the peptide that, in turn, influence supramolecular properties associated to membranes that may result in toxicity, including: 1), an ability of the peptide to strongly associate with the membrane; 2), a reduction of lateral membrane cohesive forces; and 3), a capacity to break the transbilayer gradient and puncture sealed vesicles.

Alzheimer Disease↗
PubMed1994

Antimicrobial peptides from skin secretions of Rana esculenta. Molecular cloning of cDNAs encoding esculentin and brevinins and isolation of new active peptides.

Three cytolytic peptides, termed brevinin-1E, brevinin-2E, and esculentin, were isolated from skin secretions of the European frog Rana esculenta (Simmaco, M., Mignogna, G., Barra, D., and Bossa, F. (1993) FEBS Lett. 324, 159-161). Nucleotide sequence analysis of cDNAs coding for the corresponding precursors revealed that in all of them a single copy of the sequence of the mature peptide is present preceded by a dibasic cleavage site and followed by a stop codon. The signal peptides of these precursors show a clear homology to the corresponding region of the precursor of dermorphin, a neuropeptide occurring in the skin of amphibians of the subfamily Phyllomedusinae. Ten new peptides, ranging in size from 24 to 46 residues, all possessing an intramolecular disulfide bridge located at the carboxyl-terminal end, were isolated from skin secretions of R. esculenta. These peptides can be grouped into four subfamilies on the basis of their distinctive structural and/or functional properties. All of these new peptides have antimicrobial and/or hemolytic activities typical for the respective subfamily. In addition, we demonstrate that esculentin-1 also inhibits the growth of Pseudomonas aeruginosa, Candida albicans, and Saccharomyces cerevisiae.

Amino Acid Sequence↗
PubMed1999

NMR studies of the structure and dynamics of peptide E, an endogenous opioid peptide that binds with high affinity to multiple opioid receptor subtypes.

Structural and dynamic properties of opioid peptide E have been examined in an sodium dodecyl sulfate (SDS) micelle. Structural and dynamic studies both indicate that this peptide exhibits greater segmental mobility than typical structured proteins. An nmr structural analysis of adrenal peptide E in SDS micelles indicated the presence of two well-defined beta-turns, one at the N-terminus encompassing residues 3 to 6, and the second in the region between residues 15 and 18. Certain side chain dihedral angles were also remarkably well defined, such as the chi 1 angle of F4, which exhibited a trans configuration. These calculated structures were based on a set of 9.5 restraints per residue. The backbone dynamics of peptide E in SDS micelles were examined through an analysis of 15N-relaxation parameters. An extended model-free analysis was used to interpret the relaxation data. The overall rotational correlation time is 19.7 ns. the average order parameter S2 is 0.66 +/- 0.15. The N-terminal loop region residues including G3 to R6 have an average order parameter of 0.70 +/- 0.23. The average order parameter lies somewhere between that observed for a random coil (e.g., S2 = 0.3) and that of a well-defined tertiary fold (e.g., S2 = 0.86). This suggests that peptide E in SDS micelles adopts a restricted range of conformations rather than a random coil. Based on the helical structure recently obtained for the highly homologous kappa-agonist dynorphin-A(1-17) and the beta-turn in the same region of peptide E, it is reasonable to assume that these two elements of secondary structure reflect different receptor subtype binding geometries. The intermediate order parameters observed for peptide E in an SDS micelle suggest a degree of dynamic mobility that may enable facile interconversion between helical and beta-turn geometries in the N-terminal agonist domain.

Amino Acid Sequence↗
PubMed2000

Dissociation of the peptide bond in protonated peptides.

The dissociation of the amide (peptide) bond in protonated peptides, [M + H](+), is discussed in terms of the structures and energetics of the resulting N-terminal b(n) and C-terminal y(n) sequence ions. The combined data provide strong evidence that dissociation proceeds with no reverse barriers through interconverting proton-bound complexes between the segments emerging upon cleavage of the protonated peptide bond. These complexes contain the C-terminal part as a smaller linear peptide (amino acid if one residue) and the N-terminal part either as an oxazolone or a cyclic peptide (cyclic amide if one residue). Owing to the higher thermodynamic stability but substantially lower gas-phase basicity of cyclic peptides vs isomeric oxazolones, the N-terminus is cleaved as a protonated oxazolone when ionic (b(n) series) but as a cyclic peptide when neutral (accompanying the C-terminal y(n) series). It is demonstrated that free energy correlations can be used to derive thermochemical data about sequence ions. In this context, the dependence of the logarithm of the abundance ratio log[y(1)/b(2)], from protonated GGX (G, glycine; X, varying amino acid) on the gas-phase basicity of X is used to obtain a first experimental estimate of the gas-phase basicity of the simplest b-type oxazolone, viz. 2-aminomethyl-5-oxazolone (b(2) ion with two glycyl residues).

Journal Article↗
PubMed1989

Structure of conformationally constrained peptides: from model compounds to bioactive peptides.

The use of backbone conformational constraints has acquired increasing importance in the design and synthesis of structurally restricted agonists and antagonists of bioactive peptides. Here I discuss the preferred conformations of four among the most popular types of such peptide surrogates: (a) Peptides from C alpha, alpha-dialkylated residues, (b) tetrazolyl peptides, (c) (gamma- and delta-) lactam-containing peptides, and (d) thiated peptides. Emphasis is given to conformational energy computations and x-ray diffraction analyses of selected model compounds and analogues of small bioactive peptides such as the formylmethionyl tripeptide chemoattractant and MIF.

Models, Molecular↗
PubMed1989

Inhibition of T cell response with peptides is influenced by both peptide-binding specificity of major histocompatibility complex molecules and susceptibility of T cells to blocking.

Synthetic peptides corresponding to sequences 46-62 and 51-62 of mouse lysozyme and 46-61 of hen egg-white lysozyme (HEL) were used as competitors in a variety of T cell responses. The competitors, according to their binding specificity for major histocompatibility complex (MHC) were expected to inhibit T cell responses restricted to I-Ak, but not those restricted to I-Ad, I-Ek molecules. In competition experiments with T cell hybridomas, the poor binder I-Ed molecule required 10- to 15-fold higher competitor concentrations than the good binder I-Ak molecule to achieve 50% inhibition of antigen presentation. Similarly, the nonresponder state of H-2d mice to HEL peptide 46-61 could be overcome by increasing the immunizing dose, and proliferative T cell responses to different antigens in association with a variety of class II MHC molecules could be blocked by the mouse lysozyme and HEL peptides. Thus, the capability of some and failure of other MHC molecules to bind certain peptides appeared quantitative, rather than of an all or none nature, in these experimental systems. The susceptibility of uncloned T cell lines to peptide competitors was found to decrease with time. Lines maintained by repeated restimulation with antigen and APC, but without exogenous interleukin 2, acquired resistance within weeks. In contrast, T cell clones retained their susceptibility to peptide competitors over a long period of time. The latter data raise the possibility that a competition between ubiquitous (self) peptides and foreign antigen may result in the selection of T cells that have high avidity for the activating antigen-MHC complex, and are thus relatively resistant to competition at the level of antigen presentation.

Amino Acid Sequence↗
PubMed1994

Hypoxia induces release of atrial natriuretic peptide in rat atrial tissue: a role for this peptide during low oxygen stress.

A variety of different factors have been shown to induce release of atrial natriuretic peptide from atrial tissue. Among these, stretching of atrial myocytes is considered the most important. In a recent study we showed that atrial natriuretic peptide increased cGMP and reduced lactate accumulation during hypoxia in rat ventricular myocardium. This suggests that atrial natriuretic peptide has a beneficial metabolic effect during hypoxia and raises the question whether hypoxia alone induces release of atrial natriuretic peptide. The right atrium and pieces of the right ventricle, from rats, were incubated in polyethylene vials containing 3 ml Krebs bicarbonate buffer equilibrated with 75% N2 + 20% O2 + 5% CO2 (= hypoxic conditions) or 95% O2 + 5% CO2 (= normoxic conditions). After 10 min, the ventricular tissues and aliquots of the buffer were frozen. Cyclic GMP was analyzed in the ventricular tissue and atrial natriuretic peptide was analyzed in the buffer samples. The results show that the release of atrial natriuretic peptide during hypoxia significantly exceeds the release under normoxic conditions. The hypoxia-induced release of atrial natriuretic peptide over time is characterized by an s-shaped curve with the steepest slope after about 10 min. In the presence of atrial tissue the intracellular level of cGMP in ventricular myocardium increased from 0.3 +/- 0.1 to 2.6 +/- 0.9 pmol/g w wt (P = 0.033, n = 6). We conclude that ANP is released from atrial tissue and induces increased formation of cGMP in ventricular myocardium when oxygen tension is low.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1996

Refined peptide HLA-B*3501 binding motif reveals differences in 9-mer to 11-mer peptide binding.

HLA-B*3501 is associated with subacute thyroiditis and fast progression of AIDS. An important prerequisite to investigate the T-cell recognition of HLA-B*3501-restricted antigens is the characterization of peptide-HLA-B*3501 interactions. In this study, peptide-HLA-B*3501 interactions were determined in quantitative peptide binding assays. The results were statistically analyzed to evaluate the influence of both anchor and nonanchor positions and the predictability of peptide binding. The binding data demonstrated that all anchor residues at position 2 and the C-terminus found in 9-mers functioned equally as anchors in 10-mers and 11-mers. These minimum requirements of peptide binding were refined by assessing positive and negative effects of nonanchor residues. Aliphatic hydrophobic residues at positions 3, 5, and 8 of 10-mers and position 3 of 11-mers significantly enhanced HLA-B*3501 binding. Similar effects rendered aromatic, bulky residues, acidic or polar residues of 11-mers at position 1 as well as at positions 4, 8, and 10, respectively. Negative effects were observed for residues carrying positively charged side-chains at position 7 of 11-mers. The refined HLA-B*3501 peptide binding motifs enhanced the identification of potential T-cell epitopes. The disparity between positive effects at the middle and C-terminal part (positions 5 - 8 and 10) of 11-mers and shorter peptides supports the extrusion of 11-mer residues at positions 5, 6, and 7, away from the HLA-B*3501 binding cleft.

Amino Acid Sequence↗
PubMed2000

Functional analysis of the leader peptide of the yeast gene CPA1 and heterologous regulation by other fungal peptides.

The 25-amino-acid leader peptide present at the 5' end of yeast CPA1 mRNA is responsible for the translational repression of that gene by arginine. We show here that the active domain of the yeast peptide is highly specific and extends over amino acids 6-23. The region between amino acids 6-21 is well conserved between similar peptides present upstream of CPA1-homologous genes in other fungi. The Neurospora crassa arg-2 peptide represses the expression of CPA1, whereas the peptide from Aspergillus nidulans has only a weak regulatory effect. Such results suggest that the N- and C-terminal amino acids of the peptide may influence its regulatory activity. We also show that the transcription start sites of CPA1 are not modified when the cells are grown in the presence of arginine, nor in a strain carrying an inactive peptide.

Amino Acid Sequence↗
PubMed1995

A novel approach to the design of potent bioactive peptides by incorporation of proline brackets: antiplatelet effects of Arg-Gly-Asp peptides.

Enhancing the potency of peptides is a critical and important step in the development of peptide drugs. We have proposed that proline residues flanking protein-protein interaction sites perform a structural role in enhancing their interaction [R.M. Kini and H.J. Evans, Biochem. Biophys. Res. Commun. 212 (1995) 1115-1124]. To test this theory, we incorporated proline residues on either or both sides of the interaction site of an antiplatelet peptide, IARGDMNA and determined the inhibitory potency of the peptides in whole blood aggregation. Inclusion of one proline residue, on either the amino or carboxy terminal side of the interaction site, enhances the antiplatelet activity to approximately the same extent (1.5- to 2.5-fold). Incorporation of proline residues on both sides enhances the activity by 7- to 13-fold. This enhancement of the biological activity of the peptide is probably due to a reduction in the number of possible conformations of the peptide, without introducing the rigidity that would accompany cyclization. Incorporation of proline brackets thus provides a novel approach to the design and development of more potent peptide drugs and ligands.

Amino Acid Sequence↗
PubMed1983

Hyperthermic responses to central injections of some peptide and non-peptide opioids in the guinea-pig.

Intracerebroventricular administration of prototype non-peptide opioid receptor (mu, kappa, sigma) agonists, morphine, ketocyclazocine and N-allyl normetazocine (SKF 10,047) and an agonist at both kappa and sigma receptors, pentazocine, induced hyperthermia in guinea-pigs. Similar administration of peptide opioids like beta-endorphin (BE), methionine enkephalin (Met-E), leucine enkephalin (Leu-E) and their synthetic analogues D-ala2-methionine-enkephalinamide (D-ala2-Met-E) and D-ala2-leucine-enkephalinamide (D-ala2-Leu-E) also caused hyperthermia. Of the three anion transport systems (iodide, hippurate and liver-like) present in the choroid plexus, only the liver-like transport system seems to be important to central inactivation of beta-endorphin, D-ala2-Met-enkephalin and D-ala2-Leu-enkephalin since iodipamide (an inhibitor of the liver-like transport system) augmented the hyperthermia. Prostaglandins (PG) and norepinephrine (NE) were not involved in peptide- and non-peptide opioid-induced hyperthermia because a prostaglandin synthesis inhibitor, indomethacin, and an alpha-adrenergic receptor blocker, phenoxybenzamine, had no thermolytic effect. Likewise cAMP was not required since a phosphodiesterase inhibitor, theophylline, did not accentuate the hyperthermia due to administration of peptide and non-peptide opioids. Naloxone-sensitive receptors were involved in the induction of hyperthermia by morphine and beta-endorphin since naloxone attenuated the effect. In contrast, the hyperthermic responses to ketocyclazocine, SKF 10,047, pentazocine, Met-enkephalin, Leu-enkephalin, D-ala2-Met-enkephalin and D-ala2-Leu-enkephalin were not antagonized by naloxone. Lack of antagonism of naloxone on pyrogen, arachidonic acid, PGE2, dibutyryl cAMP and NE-induced hyperthermia indicates that endogenous opioid peptides are not likely to be central mediators of the hyperthermia induced by these agents.

Animals↗
PubMed1984

Opiate activity of peptides derived from the three opioid peptide families on the rat vas deferens.

The inhibitory activity of opioid peptides derived from pro-opiomelanocortin (POMC), pro-enkephalin A and pro-enkephalin B (= pro-dynorphin) on the electrically evoked twitch of the rat vas deferens (RVD) was evaluated. The POMC-derived beta-endorphin exhibits the greatest potency on this preparation. In addition, all peptides derived from pro-enkephalin A show full agonistic activity with BAM-22P and peptide E as the most potent peptides. In contrast, the majority of peptides derived from pro-enkephalin B (= pro-dynorphin) were essentially inactive on this tissue. Moreover, no antagonistic properties of these peptides were demonstrable in this preparation; thus the opioid receptors present in the RVD (putative epsilon receptors) might not possess any particular affinity for the pro-enkephalin B derived peptides.

Animals↗
PubMed1995

Relative implication of peptide residues in binding to major histocompatibility complex class I H-2Db: application to the design of high-affinity, allele-specific peptides.

The H-2Db peptide sequence SMIENLEYM was manipulated (N- and C-terminus truncation and alanine substitution) to determine the role of structural elements (peptide ends and residue side chains) in binding to H-2Db. We found that good binding affinity could be obtained by compensating the minimal binding condition for one element by the optimal condition of the other element. In particular, we showed, that although the minimal binding sequence could be as short as a heptamer (deletion of positions 1 and 2), it needed the presence of optimal amino acids at other positions (IENLEYM). Conversely, the structurally minimal peptide would accept multiple alanine residues, but required the optimal nonameric length (AAAENAEAA). Positions 1, 2, 3, 4, 5, 7 and 9, but not 6 and 8, were involved in the H-2Db-peptide interaction. Most residues interacted directly with the MHC molecule via their main chain (amino and carboxyl) atoms (positions 1 and 2), their side chains (positions 3 and 5), or both (position 9). Positions 4 and 7 were found to play an indirect role, probably by influencing the secondary structure. At the C-terminus, the presence of a residue at position 9, but not the hydrophobic nature of its side chain, was mandatory for binding. At the N-terminus, the role of the residue at position 1 was of either minor or critical importance depending on the presence or not of a strong auxiliary anchor at position 3. The indirect contribution of residue side chains at positions 4 and 7 reflected the importance of dynamic components in the binding process. Based on these results, we designed a series of high-affinity, H-2Db selective peptides derived from the sequence X1 AIX4NAEAL, where X1 = Y or K and X4 = E or K. After radioiodination or fluorescent (FITC) labelling, these peptides bound strongly and specifically to the surface of viable H-2Db-expressing cells. Rationally designed synthetic peptides, either alone or in a stable complex with MHC, might be of value for controlling CTL activity.

Alleles↗