scholarly journals Amino acid sequence of the α subunit and computer modelling of the α and β subunits of echicetin from the venom of Echis carinatus (saw-scaled viper)

1997 ◽  
Vol 323 (2) ◽  
pp. 533-537 ◽  
Author(s):  
János POLGÁR ◽  
Edith M. MAGNENAT ◽  
Manuel C. PEITSCH ◽  
Timothy N. C. WELLS ◽  
Mansoor S. A. SAQI ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Computer Modelling ◽  
Platelet Glycoprotein ◽  
Β Subunit ◽  
Α Subunit ◽  
Echis Carinatus ◽  
Α And Β Subunits ◽  
Lectin Protein ◽  
Von Willebrand

Echicetin, a heterodimeric protein from the venom of Echis carinatus, binds to platelet glycoprotein Ib (GPIb) and so inhibits platelet aggregation or agglutination induced by various platelet agonists acting via GPIb. The amino acid sequence of the β subunit of echicetin has been reported and found to belong to the recently identified snake venom subclass of the C-type lectin protein family. Echicetin α and β subunits were purified. N-terminal sequence analysis provided direct evidence that the protein purified was echicetin. The paper presents the complete amino acid sequence of the α subunit and computer models of the α and β subunits. The sequence of α echicetin is highly similar to the α and β chains of various heterodimeric and homodimeric C-type lectins. Neither of the fully reduced and alkylated α or β subunits of echicetin inhibited the platelet agglutination induced by von Willebrand factor–ristocetin or α-thrombin. Earlier reports about the inhibitory activity of reduced and alkylated echicetin β subunit might have been due to partial reduction of the protein.

Human pituitary thyrotropin. The primary structure of the α and β subunits

1977 ◽  
Vol 55 (7) ◽  
pp. 755-760 ◽  
Author(s):  
M. R. Sairam ◽  
Choh Hao Li
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Primary Structure ◽  
Carbohydrate Moiety ◽  
Amino Acid Residues ◽  
Β Subunit ◽  
Human Pituitary ◽  
Α Subunit ◽  
Α And Β Subunits

The amino acid sequence of the α and β subunits of human pituitary thyrotropin has been proposed based on the data derived from the tryptic and chymotryptic peptides. The α subunit consists of 89 amino acid residues with two carbohydrate moieties, presumably linked to asparagines in position 49 and 75, and its amino acid sequence is identical to that of lutropin α. The β subunit has 112 residues with a single carbohydrate moiety attached to asparagine at position 23. Comparison of the primary structure of human thyrotropin β with that of the bovine hormone reveals that only 11 residue positions have been found to be different.

scholarly journals The Amino Acid Sequence of the A Protein (α Subunit) of the Tryptophan Synthetase of Escherichia coli

1967 ◽  
Vol 242 (22) ◽  
pp. 5442-5446 ◽  
Author(s):  
John R. Guest ◽  
Gabriel R. Drapeau ◽  
Bruce C. Carlton ◽  
Charles Yanofsky
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Α Subunit ◽  
Tryptophan Synthetase

scholarly journals Rapid purification and characterization of human platelet glycoprotein V: the amino acid sequence contains leucine-rich repetitive modules as in glycoprotein Ib

Blood ◽  
1990 ◽  
Vol 75 (12) ◽  
pp. 2349-2356 ◽  
Author(s):  
T Shimomura ◽  
K Fujimura ◽  
S Maehama ◽  
M Takemoto ◽  
K Oda ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Structural Model ◽  
Consensus Sequence ◽  
Reversed Phase ◽  
Platelet Glycoprotein ◽  
Lectin Affinity Chromatography ◽  
Glycoprotein Ib ◽  
Simple Method ◽  
Carbohydrate Chains

Glycoprotein V (GPV) is a membrane-associated, 82 Kd platelet glycoprotein that is hydrolyzed during thrombin activation to yield 69 Kd fragment. We have developed a rapid and simple method for isolation of the protein from platelet extracts using a combination of gel permeation, anion-exchange, and lectin affinity chromatography. The partial amino acid sequence was determined by analysis of peptides generated by digestion of the S-carboxyamido-methylated protein with Achromobacter protease I or cyanogen bromide. The sequence shows a remarkable periodicity of leucine residues, which is homologous to the consensus sequence of a highly diversified protein super-family with a common repetitive module. Thrombin cleavage site was determined to be located at the C-terminal region of GPV by analysis of the products separated by sizing and reversed-phase high performance liquid chromatography. By lectin blot analysis, the existence of mucin-type carbohydrate chains was indicated, as well as the existence of asparagine-linked carbohydrate chains shown by the amino acid sequence analysis. From these data, we report a structural model of GPV that is analogous to glycoprotein Ib.

scholarly journals The von willebrand factor domain-mediating botrocetin-induced binding to glycoprotein IB lies between Val449 and Lys728

Blood ◽  
1987 ◽  
Vol 70 (4) ◽  
pp. 985-988 ◽  
Author(s):  
Y Fujimura ◽  
LZ Holland ◽  
ZM Ruggeri ◽  
TS Zimmerman
Keyword(s):  
Monoclonal Antibodies ◽  
Amino Acid ◽  
Von Willebrand Factor ◽  
Amino Acid Residue ◽  
Von Willebrand Disease ◽  
Platelet Glycoprotein ◽  
Tryptic Fragment ◽  
Alternative Agent ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Botrocetin, a component of Bothrops jararaca venom, induces von Willebrand factor (vWF)-dependent platelet agglutination and has been proposed as an alternative agent to ristocetin for evaluating vWF function. However, important differences between the vWF-platelet interactions induced by these two agents have suggested that different regions of vWF and the platelet may be involved in the interactions induced by the two agonists. We have recently demonstrated that binding of vWF to the platelet glycoprotein (GP) Ib receptor, either induced by ristocetin or as occurs spontaneously with asialo-vWF or vWF from IIb von Willebrand disease, is mediated by a domain residing on a 52/48- kilodalton (kD) tryptic fragment of vWF. This fragment extends from amino acid residue Val (449) to Lys (728). We have now found that this 52/48-kD fragment blocks botrocetin-induced binding of vWF to platelets and completely inhibits botrocetin-induced platelet agglutination. These results provide evidence that the vWF domain-mediating, botrocetin-induced platelet agglutination lies within the region delimited by this fragment and is therefore close to or identical with that which mediates ristocetin-induced binding and spontaneous binding of vWF to platelet GPIb. Anti-GPIb monoclonal antibodies also blocked agglutination, which showed that botrocetin, like ristocetin, induces binding of vWF to the GPIb receptor.

scholarly journals Targeted Disruption of a Fungal G-Protein β Subunit Gene Results in Increased Vegetative Growth but Reduced Virulence

1997 ◽  
Vol 10 (8) ◽  
pp. 984-993 ◽  
Author(s):  
Shin Kasahara ◽  
Donald L. Nuss
Keyword(s):  
Amino Acid ◽  
G Protein ◽  
Vegetative Growth ◽  
Synthetic Medium ◽  
Cryphonectria Parasitica ◽  
Β Subunit ◽  
Subunit Gene ◽  
Targeted Disruption ◽  
Fungal Virulence ◽  
Α Subunit

Targeted disruption of two G-protein α subunit genes in the chestnut blight fungus Cryphonectria parasitica revealed roles for the Giα subunit CPG-1 in fungal reproduction, virulence, and vegetative growth. A second Gα subunit, CPG-2, was found to be dispensable for these functions. We now report the cloning and targeted disruption of a C. parasitica G-protein β subunit gene. The deduced amino acid sequence encoded by this gene, designated cpgb-1, was found to share 66.2, 65.9, and 66.7% amino acid identity with Gβ homologues from human, Drosophila, and Dictyostelium origins, respectively, but only 39.7% identity with the Saccharomyces cerevisiae Gβ homologue STE4 product. Low stringency Southern hybridization failed to detect any related Gβ subunit genes in C. parasitica. Targeted disruption of cpgb-1 resulted in several of the changes previously reported to accompany disruption of the C. parasitica Giα subunit gene cpg-1. These included very significant reductions in pigmentation, asexual sporulation, and virulence. In contrast to results obtained for Giα gene disruption, the reduction in virulence resulting from the disruption of a Gβ gene was accompanied by increased, rather than decreased, vegetative growth on synthetic medium. The relevance of these results to mechanisms of fungal virulence is considered.

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