scholarly journals Four Amino Acid Residues Are Critical for High Affinity Binding of Neuromedin B to the Neuromedin B Receptor

1998 ◽  
Vol 273 (26) ◽  
pp. 15927-15932 ◽  
Author(s):  
Eduardo Sainz ◽  
Mark Akeson ◽  
Samuel A. Mantey ◽  
Robert T. Jensen ◽  
James F. Battey
Keyword(s):  
Amino Acid ◽  
Affinity Binding ◽  
Amino Acid Residues ◽  
High Affinity Binding ◽  
High Affinity ◽  
Neuromedin B

scholarly journals Alternative ligands as probes for the carotenoid-binding site of lobster carapace crustacyanin

1990 ◽  
Vol 265 (3) ◽  
pp. 919-921 ◽  
Author(s):  
J B Clarke ◽  
E E Eliopoulos ◽  
J B C Findlay ◽  
P F Zagalsky
Keyword(s):  
Amino Acid ◽  
Binding Site ◽  
Binding Sites ◽  
Amino Acid Sequences ◽  
Fluorescence Probes ◽  
Affinity Binding ◽  
Hydrophobic Pocket ◽  
High Affinity Binding ◽  
High Affinity ◽  
Parinaric Acid

The apoproteins of the lobster carotenoprotein, crustacyanin, show single high-affinity binding sites for the hydrophobic fluorescence probes 8-anilo-1-naphthalenesulphonic acid and cis-parinaric acid, and exhibit fluorescence transfer from tryptophan to the ligands. These results, together with information from the amino acid sequences, infer that the native carotenoid, astaxanthin, is bound to each apoprotein within an internal hydrophobic pocket, or calyx.

DOMAIN OF BINDING ACTIVITY WITH PLASMIN KRINGLE IN SYNTHESIZED C-TERMINAL PEPTIDES , OF α2-PLASMIN INHIBITOR

1987 ◽  
Author(s):  
M Iwamoto ◽  
N Sugiyama ◽  
T Sasaki ◽  
Y Abiko
Keyword(s):  
Binding Site ◽  
Apparent Rate Constant ◽  
Binding Activity ◽  
Affinity Binding ◽  
Amino Acid Residues ◽  
Terminal Part ◽  
High Affinity Binding ◽  
Tryptic Fragment ◽  
High Affinity ◽  
Plasmin Inhibitor

The inhibitory reaction between plasmin and α2-plasmin inhibitor (α2-PI) proceeds with two steps, a very fast reversible reaction followed by a slower irreversible transition. The first step is dependent on the interaction between lysine binding site (LBS) of plasmin and the corresponding complementary site of α2-PI (kringle binding site(KBS)). It has been reported that KBS is located in a C-terminal tryptic fragment (T-11; J. Biochem. 99, 1699 (1986)).In order to investigate which amino acid residues of T-ll play important roles in binding of plasmin kringle, we tested inhibitory activity of synthesized peptides on the apparent rate constant in the reaction between α2-PI and plasmin. 50% inhibition concentrations of T-ll, peptide I, II, III and IV were 7, 18, 13, 35 and 250pM respectively, indicating that Leu9-Lysl0 is an important part for binding of T-ll to LBS. Peptide III lost its activity by depletion or amidation of the C-terminal lysine residue.In the system consisted of α2-PI and miniplasmin which lacked kringle 1-4, peptide I did not inhibit the interaction between them. Furthermore, peptide II competitively inhibited the binding of tranexamic acid to kringle 1-3 (Ki 0.85μM).These findings suggest that the C-terminal part is involved in the high affinity binding of α2-PI to plasmin kringle and that LyslO in T-ll and C-terminal carboxyl residue play crucial roles in binding to LBS of kringle.

scholarly journals New World Arenavirus Clade C, but Not Clade A and B Viruses, Utilizes α-Dystroglycan as Its Major Receptor

2002 ◽  
Vol 76 (10) ◽  
pp. 5140-5146 ◽  
Author(s):  
Christina F. Spiropoulou ◽  
Stefan Kunz ◽  
Pierre E. Rollin ◽  
Kevin P. Campbell ◽  
Michael B. A. Oldstone
Keyword(s):  
Amino Acid ◽  
New World ◽  
Embryonic Stem ◽  
Amino Acid Position ◽  
Affinity Binding ◽  
Aliphatic Amino Acid ◽  
High Affinity Binding ◽  
Old World ◽  
High Affinity ◽  
Clade C

ABSTRACT α-Dystroglycan (α-DG) has been identified as a major receptor for lymphocytic choriomeningitis virus (LCMV) and Lassa virus, two Old World arenaviruses. The situation with New World arenaviruses is less clear: previous studies demonstrated that Oliveros virus also exhibited high-affinity binding to α-DG but that Guanarito virus did not. To extend these initial studies, several additional Old and New World arenaviruses were screened for entry into mouse embryonic stem cells possessing or lacking α-DG. In addition, representative viruses were further analyzed for direct binding to α-DG by means of a virus overlay protein blot assay technique. These studies indicate that Old World arenaviruses use α-DG as a major receptor, whereas, of the New World arenaviruses, only clade C viruses (i.e., Oliveros and Latino viruses) use α-DG as a major receptor. New World clade A and B arenaviruses, which include the highly pathogenic Machupo, Guanarito, Junin, and Sabia viruses, appear to use a different receptor or coreceptor for binding. Previous studies with LCMV have suggested the need for a small aliphatic amino acid at LCMV GP1 glycoprotein amino acid position 260 to allow high-affinity binding to α-DG. As reported herein, this requirement appears to be broadly applicable to the arenaviruses as determined by more extensive analysis of α-DG receptor usage and GP1 sequences of Old and New World arenaviruses. In addition, GP1 amino acid position 259 also appears to be important, since all arenaviruses showing high-affinity α-DG binding possess a bulky aromatic amino acid (tyrosine or phenylalanine) at this position.

scholarly journals Comparison of Target Recognition by TRAF1 and TRAF2

2020 ◽  
Vol 21 (8) ◽  
pp. 2895
Author(s):  
Chang Min Kim ◽  
Hyun Ho Park
Keyword(s):  
Receptor Binding ◽  
Target Recognition ◽  
Affinity Binding ◽  
Binding Affinities ◽  
Amino Acid Residues ◽  
Critical Determinant ◽  
High Affinity Binding ◽  
High Affinity ◽  
Caspase 2

Although TRAF1 and TRAF2 share common receptors and have extremely conserved amino acid residues, recent studies have shown that key differences in receptor binding preferences with different affinities exist, which might be important for their different functions in TRAF-mediated signal transduction. To better understand TRAF1 and TRAF2 signaling, we analyzed and compared their receptor binding-affinities. Our study revealed that TRADD, TANK, and caspase-2 bind to both TRAF1 and TRAF2 with different affinities in vitro. Sequence and structural analyses revealed that S454 on TRAF2 (corresponding to A369 of TRAF1) is critical for the binding of TRADD, and F347 on TRAF1 (corresponding to L432 of TRAF2) is a critical determinant for high affinity binding of TANK and caspase-2.

Characterization of a Mode of Specific Binding of Fibrin Monomer through its Amino-Terminal Domain by Macrophages and Macrophage Cell-Lines

1990 ◽  
Vol 63 (02) ◽  
pp. 193-203 ◽  
Author(s):  
John R Shainoff ◽  
Deborah J Stearns ◽  
Patricia M DiBello ◽  
Youko Hishikawa-Itoh
Keyword(s):  
Peritoneal Macrophages ◽  
Affinity Binding ◽  
Macrophage Cell ◽  
High Affinity Binding ◽  
Amino Terminal ◽  
High Affinity ◽  
Terminal Domain ◽  
Weak Binding ◽  
Amino Terminal Domain

SummaryThe studies reported here probe the existence of a receptor-mediated mode of fibrin-binding by macrophages that is associated with the chemical change underlying the fibrinogen-fibrin conversion (the release of fibrinopeptides from the amino-terminal domain) without depending on fibrin-aggregation. The question is pursued by 1) characterization of binding in relation to fibrinopeptide content of both the intact protein and the CNBr-fragment comprising the amino-terminal domain known as the NDSK of the protein, 2) tests of competition for binding sites, and 3) photo-affinity labeling of macrophage surface proteins. The binding of intact monomers of types lacking either fibrinopeptide A alone (α-fibrin) or both fibrinopeptides A and B (αβ-fibrin) by peritoneal macrophages is characterized as proceeding through both a fibrin-specific low density/high affinity (BMAX ≃ 200–800 molecules/cell, KD ≃ 10−12 M) interaction that is not duplicated with fibrinogen, and a non-specific high density/low affinity (BMAX ≥ 105 molecules/cell, KD ≥ 10−6 M) interaction equivalent to the weak binding of fibrinogen. Similar binding characteristics are displayed by monocyte/macrophage cell lines (J774A.1 and U937) as well as peritoneal macrophages towards the NDSK preparations of these proteins, except for a slightly weaker (KD ≃ 10−10 M) high-affinity binding. The high affinity binding of intact monomer is inhibitable by fibrin-NDSK, but not fibrinogen-NDSK. This binding appears principally dependent on release of fibrinopeptide-A, because a species of fibrin (β-fibrin) lacking fibrinopeptide-B alone undergoes only weak binding similar to that of fibrinogen. Synthetic Gly-Pro-Arg and Gly-His-Arg-Pro corresponding to the N-termini of to the α- and the β-chains of fibrin both inhibit the high affinity binding of the fibrin-NDSKs, and the cell-adhesion peptide Arg-Gly-Asp does not. Photoaffinity-labeling experiments indicate that polypeptides with elec-trophoretically estimated masses of 124 and 187 kDa are the principal membrane components associated with specifically bound fibrin-NDSK. The binding could not be up-regulated with either phorbol myristyl acetate, interferon gamma or ADP, but was abolished by EDTA and by lipopolysaccharide. Because of the low BMAX, it is suggested that the high-affinity mode of binding characterized here would be too limited to function by itself in scavenging much fibrin, but may act cooperatively with other, less limited modes of fibrin binding.

High Affinity Binding Sites for Activated Protein C and Protein C on Cultured Human Umbilical Vein Endothelial Cells

1994 ◽  
Vol 72 (03) ◽  
pp. 465-474 ◽  
Author(s):  
Neelesh Bangalore ◽  
William N Drohan ◽  
Carolyn L Orthner
Keyword(s):  
Binding Sites ◽  
Protein C ◽  
Umbilical Vein ◽  
Activated Protein C ◽  
Affinity Binding ◽  
Cell Binding ◽  
High Affinity Binding ◽  
High Affinity ◽  
Gla Domain ◽  
Umbilical Vein Endothelial Cells

SummaryActivated protein C (APC) is an antithrombotic serine proteinase having anticoagulant, profibrinolytic and anti-inflammatory activities. Despite its potential clinical utility, relatively little is known about its clearance mechanisms. In the present study we have characterized the interaction of APC and its active site blocked forms with human umbilical vein endothelial cells (HUVEC). At 4° C 125I-APC bound to HUVEC in a specific, time dependent, saturable and reversible manner. Scatchard analysis of the binding isotherm demonstrated a Kd value of 6.8 nM and total number of binding sites per cell of 359,000. Similar binding isotherms were obtained using radiolabeled protein C (PC) zymogen as well as D-phe-pro-arg-chloromethylketone (PPACK) inhibited APC indicating that a functional active site was not required. Competition studies showed that the binding of APC, PPACK-APC and PC were mutually exclusive suggesting that they bound to the same site(s). Proteolytic removal of the N-terminal γ-carboxyglutamic acid (gla) domain of PC abolished its ability to compete indicating that the gla-domain was essential for cell binding. Surprisingly, APC binding to these cells appeared to be independent of protein S, a cofactor of APC generally thought to be required for its high affinity binding to cell surfaces. The identity of the cell binding site(s), for the most part, appeared to be distinct from other known APC ligands which are associated with cell membranes or extracellular matrix including phospholipid, thrombomodulin, factor V, plasminogen activator inhibitor type 1 (PAI-1) and heparin. Pretreatment of HUVEC with antifactor VIII antibody caused partial inhibition of 125I-APC binding indicating that factor VIII or a homolog accounted for ∼30% of APC binding. Studies of the properties of surface bound 125I-APC or 125I-PC and their fate at 4°C compared to 37 °C were consistent with association of ∼25% of the initially bound radioligand with an endocytic receptor. However, most of the radioligand appeared not to be bound to an endocytic receptor and dissociated rapidly at 37° C in an intact and functional state. These data indicate the presence of specific, high affinity binding sites for APC and PC on the surface of HUVEC. While a minor proportion of binding sites may be involved in endocytosis, the identity and function of the major proportion is presently unknown. It is speculated that this putative receptor may be a further mechanisms of localizing the PC antithrombotic system to the vascular endothelium.

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