Structural requirements of pancreatic polypeptide receptor binding

1991 ◽  
Vol 261 (3) ◽  
pp. E319-E324
Author(s):  
R. L. Gingerich ◽  
J. O. Akpan ◽  
W. R. Gilbert ◽  
K. M. Leith ◽  
J. A. Hoffmann ◽  
...  
Keyword(s):  
Amino Acid ◽  
Methyl Ester ◽  
Receptor Binding ◽  
Pancreatic Polypeptide ◽  
Free Acid ◽  
Mammalian Species ◽  
Methionine Sulfoxide ◽  
Radioreceptor Assay ◽  
Amino Acid Residues ◽  
Structural Requirements

Pancreatic polypeptide (PP) receptors have been identified and characterized on the basolateral membranes (BLM) of canine intestinal mucosa. The present study was designed to ascertain the structural requirements of the PP molecule for binding to its receptor. A radioreceptor assay using purified BLM was employed to elucidate receptors specific to PPs of various mammalian species and to modified bovine PP (bPP) fragments. Receptor cross-reactivities (CR) to various PPs and bPP fragments were established. Results show that percent receptor CR by PPs of various species was as follows: bPP (100%) greater than human PP (68%) greater than porcine PP (50%) greater than canine PP (45%) greater than ovine PP (36%) greater than rat PP (3%). The fragments bPP-(1-15), bPP-(1-17), bPP-(1-26), bPP-(16-23), bPP-(18-30), bPP-(24-36), bPP-(27-35), and bPP-(31-36) at 500 nM did not significantly displace tracer from receptor (less than 0.1% CR). Des-COOH-terminal tyrosinamide [bPP-(1-35)] produced less than 0.1% CR. Oxidation of bPP methionine-30 residue to methionine sulfoxide decreased displacement to 67%. Modification of native amidated tyrosinamide to the free acid abolished receptor binding, whereas esterification to the methyl ester of COOH-terminal tyrosine restored binding to 60%. Additionally, percent CR decreased progressively as amino acid residues were deleted from the NH2-terminal region. We conclude that the molecular homologue of PP primary structure is necessary for full receptor binding. Both the NH2- and COOH-terminal residues are required for recognition, and the COOH-terminal tyrosinamide must be intact for PP binding to its receptor.

ReaxFF-based molecular dynamics simulation of the interaction between plasma ROS and the receptor-binding domain of the spike protein in the capsid protein of SARS-CoV-2

2021 ◽  
Author(s):  
Huichao Wang ◽  
Tong Zhao ◽  
Shuhui Yang ◽  
Liang Zou ◽  
Xiaolong Wang ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Amino Acid ◽  
Capsid Protein ◽  
Receptor Binding ◽  
Hydrogen Abstraction ◽  
Binding Domain ◽  
Spike Protein ◽  
Receptor Binding Domain ◽  
Amino Acid Residues ◽  
Global Epidemic

Abstract Under the severe situation of the current global epidemic, researchers have been working hard to find a reliable way to suppress the infection of the virus and prevent the spread of the epidemic. Studies have shown that the recognition and binding of human angiotensin-converting enzyme 2 (ACE2) by the receptor-binding domain (BRD) of spike protein on the surface of SARS-CoV-2 is a crucial step for SARS-CoV-2 to invade human receptor cells, and blocking this process can inhibit the virus from invading human normal cells. Plasma treatment can disrupt the structure of the RBD and effectively block the binding process. However, the mechanism by which plasma blocks the recognition and binding between the two is not clear. In this study, reaction process between reactive oxygen species (ROS) in plasma and the molecular model of RBD was simulated using a reactive molecular dynamics method. The results showed that the destruction of RBD molecule by ROS was triggered by hydrogen abstraction reactions. O and OH abstracted H atoms from RBD, while the H atoms of H2O2 and HO2 were abstracted by RBD. The hydrogen abstraction resulted in the breakage of C-H, N-H, O-H and C=O bonds and the formation of C=C, C=N bonds. The addition reaction of OH increased the number of O-H bonds and caused the formation of C-O, N-O and O-H bonds. The dissociation of N-H bonds led to the destruction of the original structure of peptide bonds and amino acid residues, change the type of amino acid residues, and caused the conversion of N-C and N=C, C=O and C-O. The simulation partially elucidated the microscopic mechanism of the interaction between ROS in plasma and the capsid protein of SARS-CoV-2, providing theoretical support for the control of SARS-CoV-2 infection by plasma, a contribution to overcoming the global epidemic problem.

scholarly journals Receptor binding of guinea pig and pig vasoactive intestinal peptides by rat lung

1988 ◽  
Vol 254 (2) ◽  
pp. 613-615 ◽  
Author(s):  
S Paul ◽  
D J Volle ◽  
J Currie
Keyword(s):  
Amino Acid ◽  
Guinea Pig ◽  
Vasoactive Intestinal Peptide ◽  
Receptor Binding ◽  
Amino Acid Residues ◽  
Rat Lung ◽  
Intestinal Peptides ◽  
Peptide Hydrolases ◽  
Vasoactive Intestinal Peptides

Guinea pig vasoactive intestinal peptide (gpVIP) differs from other mammalian VIPs in four of its 28 amino acid residues. In the present study, the gpVIP displaced 125I-labelled pig VIP (pVIP) binding by rat lung membranes with 7.7-fold lower potency than pVIP. Degradation of gpVIP by rat lung membranes, assessed by radioimmunoassay and h.p.l.c., was 1.9-fold greater than that of pVIP. This difference in degradation of the two peptides was not large enough to account for the lower receptor-binding potency of gpVIP. The amino acid residues that distinguish pVIP from gpVIP are likely to contribute to the interaction of VIP with receptors and peptide hydrolases in lung membranes.

scholarly journals Receptor Binding Domain of Escherichia coli F18 Fimbrial Adhesin FedF Can Be both Efficiently Secreted and Surface Displayed in a Functional Form in Lactococcus lactis

2004 ◽  
Vol 70 (4) ◽  
pp. 2061-2071 ◽  
Author(s):  
Agneta Lindholm ◽  
Andreas Smeds ◽  
Airi Palva
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Receptor Binding ◽  
Intestinal Epithelial Cells ◽  
Surface Display ◽  
Cell Surface Display ◽  
Binding Domain ◽  
Intestinal Epithelial ◽  
Receptor Binding Domain ◽  
Amino Acid Residues

ABSTRACT Adherence of F18 fimbrial Escherichia coli to porcine intestinal epithelial cells is mediated by the adhesin (FedF) of F18 fimbriae. In a previous study, we demonstrated the specificity of the amino acid residues between 60 and 109 as the receptor binding domain of FedF. In this study, different expression, secretion, and anchoring systems for the receptor binding domain of the FedF adhesin in Lactococcus lactis were evaluated. Two partially overlapping receptor binding domains (42 and 62 amino acid residues) were expressed as fusions with L. lactis subsp. cremoris protein PrtP for evaluation of secretion efficiency. To evaluate the cell surface display of these FedF-PrtP fusions, they were further combined with different lengths of PrtP spacers fused with either the L. lactis AcmA anchor or the PrtP cell wall binding domain. An HtrA-defective L. lactis NZ9000 mutant was constructed to determine its effect on the level of secreted or anchored fusion proteins. Recombinant L. lactis clones secreting the receptor binding domain of F18 fimbriae as a fusion with the H domains of L. lactis protein PrtP were first constructed by using two different signal peptides. FedF-PrtP fusions, directed by the signal sequence of L. brevis SlpA, were throughout found to be secreted at significantly higher quantities than corresponding fusions with the signal peptide of L. lactis Usp45. In the surface display systems tested, the L. lactis AcmA anchor performed significantly better, particularly in the L. lactis NZ9000ΔhtrA strain, compared to the L. lactis PrtP anchor region. Of the cell surface display constructs with the AcmA anchor, only those with the longest PrtP spacer regions resulted in efficient binding of recombinant L. lactis cells to porcine intestinal epithelial cells. These results confirmed that it is possible to efficiently produce the receptor binding domain of the F18 adhesin in a functionally active form in L. lactis.

scholarly journals Binding of various ovotransferrin fragments to chick-embryo red cells

1989 ◽  
Vol 257 (1) ◽  
pp. 301-304 ◽  
Author(s):  
A Oratore ◽  
G D'Andrea ◽  
K Moreton ◽  
J Williams
Keyword(s):  
Amino Acid ◽  
Chick Embryo ◽  
Red Blood Cells ◽  
Receptor Binding ◽  
Blood Cells ◽  
Tight Binding ◽  
Red Cells ◽  
Transferrin Receptors ◽  
Amino Acid Residues

1. The ability of N- and C-terminal half-molecule fragments of hen ovotransferrin to interact with chick red blood cells (CERBC) has been studied under conditions that allow binding of the transferrin to transferrin receptors to take place, but not the delivery of iron to the cell. Two kinds of half-molecule fragments were used: (a) those which can associate with one another to give a dimer resembling native transferrin and (b) those which cannot associate in this way because they lack a few amino acid residues from their C-terminal ends. 2. Neither N nor C half-molecules alone can bind to the CERBC, but, when both are present, tight binding occurs. 3. Whether or not the half-molecules can associate with one another makes little difference to receptor binding. 4. Given that one of the half-molecules is iron-saturated, the presence or absence of iron in the contralateral half-molecule again makes little difference to receptor binding.

scholarly journals Primary structure of the cytosolic β-glucosidase of guinea pig liver

1996 ◽  
Vol 319 (3) ◽  
pp. 829-837 ◽  
Author(s):  
William S HAYS ◽  
Steven A. JENISON ◽  
Takashi YAMADA ◽  
Andrzej PASTUSZYN ◽  
Robert H. GLEW
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Guinea Pig ◽  
Mammalian Species ◽  
Amino Acid Sequences ◽  
Amino Acid Residues ◽  
Pig Liver ◽  
Reading Frame ◽  
Degenerate Oligonucleotide ◽  
Guinea Pig Liver

The cytosolic β-glucosidase (EC 3.2.1.21) present in the livers of mammalian species is distinguished by its broad specificity for sugars and its preference for hydrophobic aglycones. We purified the cytosolic β-glucosidase from guinea pig liver and sequenced 142 amino acid residues contained within 12 trypsin digest fragments. Using degenerate oligonucleotide primers deduced from the peptide sequences, a 622 bp cytosolic β-glucosidase cDNA was amplified by reverse-transcriptase PCR, using total guinea pig liver RNA as template. The ‘rapid amplification of cDNA ends (RACE)’ method [Frohman (1993) Methods Enzymol. 218, 340–356] was used to synthesize the remaining segments of the full-length cDNA. The complete cDNA contained 1671 nucleotides with an open reading frame coding for 469 amino acid residues. The amino acid sequence deduced from the cDNA sequence included the amino acid sequences of all 12 trypsin digest fragments derived from the purified enzyme. Amino acid sequence analysis indicates that the guinea pig liver cytosolic β-glucosidase is a Family 1 β-glycosidase and that it is most closely related to mammalian lactase-phlorizin hydrolase. These results suggest that the cytosolic β-glucosidase and lactase-phlorizin hydrolase diverged from a common evolutionary precursor.

scholarly journals The C Terminus of Component C2II ofClostridium botulinum C2 Toxin Is Essential for Receptor Binding

2000 ◽  
Vol 68 (8) ◽  
pp. 4566-4573 ◽  
Author(s):  
Dagmar Blöcker ◽  
Holger Barth ◽  
Elke Maier ◽  
Roland Benz ◽  
Joseph T. Barbieri ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Receptor Binding ◽  
Sodium Dodecyl ◽  
Cytotoxic Action ◽  
Amino Acid Residues ◽  
C Terminus ◽  
Terminal Amino ◽  
Function Relationship ◽  
C2 Toxin

ABSTRACT The binary Clostridium botulinum C2 toxin consists of two separate proteins, the binding component C2II (80.5 kDa) and the actin-ADP-ribosylating enzyme component C2I (49.4 kDa). For its cytotoxic action, C2II binds to a cell membrane receptor and induces cell entry of C2I via receptor-mediated endocytosis. Here we studied the structure-function relationship of C2II by constructing truncated C2II proteins and producing polyclonal antisera against selective regions of C2II. An antibody raised against the C terminus (amino acids 592 to 721) of C2II inhibited binding of C2II to cells. The antibody prevented pore formation by C2II oligomers in artificial membranes but did not influence the properties of existing channels. To further define the region responsible for receptor binding, we constructed proteins with deletions in C2II; specifically, they lacked amino acid residues 592 to 721 and the 7 C-terminal amino acid residues. The truncated proteins still formed sodium dodecyl sulfate-stable oligomers but were unable to bind to cells. Our data indicate that the C terminus of C2II mediates binding of the protein to cells and that the 7 C-terminal amino acids are structurally important for receptor binding.

scholarly journals Structural requirements of platelet chemokines for neutrophil activation

Blood ◽  
1994 ◽  
Vol 84 (7) ◽  
pp. 2329-2339 ◽  
Author(s):  
Z Yan ◽  
J Zhang ◽  
JC Holt ◽  
GJ Stewart ◽  
S Niewiarowski ◽  
...  
Keyword(s):  
Amino Acid ◽  
Receptor Binding ◽  
Cysteine Residue ◽  
Neutrophil Activation ◽  
Homologous Sequence ◽  
Platelet Factor ◽  
Structural Requirements ◽  
Parent Molecule ◽  
Amino Acid Homology ◽  
Functional Features

Abstract Using recombinantly expressed proteins and synthetic peptides, we examined the structural/functional features of the platelet chemokines, neutrophil-activating peptide-2 (NAP-2) and platelet factor 4 (PF4); that were important in their activation of neutrophils. Previous studies with the chemokine interleukin-8 (IL-8) had shown that the N- terminal region preceding the first cysteine residue was critical in defining neutrophil-activating properties. We examined whether NAP-2 and PF4 had similar structural requirements. In the Ale-glu-leu-arg (AELR) N-terminus of NAP-2, substitution of E or R abolished Ca2+ mobilization and elastase secretion. Unlike the parent molecule PF4, AELR/PF4, the hybrid formed by replacing the N-terminal sequence of PF4 before the first cysteine residue with the homologous sequence of NAP- 2, stimulated Ca2+ mobilization and elastase secretion. Furthermore, the effect of amino acid substitutions in the ELR motif differed from those seen with NAP-2 in that conserved substitutions of E or R in NAP- 2 abolished activity, but only reduced neutrophil activation in the hybrid. These studies show that just as with IL-8, the N-termini of NAP- 2 and PF4 are critical for high-level neutrophil-activating function. Desensitization studies provided information on receptor binding. NAP- 2, which binds almost exclusively to the type 2 IL-8 receptor (IL-8R), did not desensitize neutrophils to activation by IL-8 because IL-8 could bind to and activate via both type 1 and 2 IL-8R. AELR/PF4 appears to bind to both types of receptors because it desensitized neutrophils to NAP-2 activation; but was not desensitized by NAP-2, and because it desensitized to and was desensitized by IL-8. Thus, although NAP-2 and AELR/PF4 share approximately 60% amino acid homology, they have different receptor affinities. Studies were performed to define the role of the C-termini of these platelet chemokines in receptor binding. Heparin and a monoclonal antibody specific for the heparin- binding domain of PF4 both inhibited Ca2+ mobilization and elastase release, further suggesting that the C-terminus of these chemokines is important in receptor binding. Synthetic NAP-2(51–70) failed to mobilize Ca2+, whereas PF4(47-–70) and PF4(58–70) induced Ca2+ mobilization and secretion of elastase at high concentrations. Pertussis toxin inhibited neutrophil activation by 40% to 50%, establishing a role for G-protein-coupled receptors such as the IL-8Rs in activation by the PF4 C-terminal peptides.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Peptide inhibitors of the interaction of the SARS-CoV-2 receptor-binding domain with the ACE2 cell receptor

2021 ◽  
Vol 67 (3) ◽  
pp. 244-250
Author(s):  
R.Sh. Bibilashvili ◽  
M.V. Sidorova ◽  
U.S. Dudkina ◽  
M.E. Palkeeva ◽  
A.S. Molokoedov ◽  
...  
Keyword(s):  
Amino Acid ◽  
Receptor Binding ◽  
Disulfide Bonds ◽  
Protein S ◽  
Cell Receptor ◽  
Binding Domain ◽  
Amino Acid Sequences ◽  
Receptor Binding Domain ◽  
Amino Acid Residues ◽  
Chimeric Molecules

Computer simulation has been used to identify peptides that mimic the natural target of the SARS-CoV-2 coronavirus spike (S) protein, the angiotensin converting enzyme type 2 (ACE2) cell receptor. Based on the structure of the complex of the protein S receptor-binding domain (RBD) and ACE2, the design of chimeric molecules consisting of two 22-23-mer peptides linked to each other by disulfide bonds was carried out. The chimeric molecule X1 was a disulfide dimer, in which edge cysteine residues in the precursor molecules h1 and h2 were connected by the S-S bond. In the chimeric molecule X2, the disulfide bond was located in the middle of the molecule of each of the precursor peptides. The precursors h1 and h2 modelled amino acid sequences of α1- and α2-helices of the extracellular peptidase domain of ACE2, respectively, keeping intact most of the amino acid residues involved in the interaction with RBD. The aim of the work was to evaluate the binding efficiency of chimeric molecules and their RBD-peptides (particularly in dependence of the middle and edge methods of fixing the initial peptides h1 and h2). The proposed polypeptides and chimeric molecules were synthesized by chemical methods, purified (to 95-97% purity), and characterized by HPLC and MALDI-TOF mass spectrometry. The binding of the peptides to the SARS-CoV-2 RBD was evaluated by microthermophoresis with recombinant domains corresponding in sequence to the original Chinese (GenBank ID NC_045512.2) and the British (B. 1.1.7, GISAID EPI_ISL_683466) variants. Binding to the original RBD of the Chinese variant was detected in three synthesized peptides: linear h2 and both chimeric variants. Chimeric peptides were also bound to the RBD of the British variant with micromolar constants. The antiviral activity of the proposed peptides in Vero cell culture was also evaluated.

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