scholarly journals Cellular functions of the Rap1 GTP-binding protein: a pattern emerges

2003 ◽  
Vol 116 (3) ◽  
pp. 435-440 ◽  
Author(s):  
E. Caron
Keyword(s):  
Binding Protein ◽  
Protein A ◽  
Cellular Functions ◽  
Gtp Binding Protein ◽  
Gtp Binding

scholarly journals Characterization of GTPase Activity of TrmE, a Member of a Novel GTPase Superfamily, from Thermotoga maritima

2000 ◽  
Vol 182 (24) ◽  
pp. 7078-7082 ◽  
Author(s):  
Kunitoshi Yamanaka ◽  
Jihwan Hwang ◽  
Masayori Inouye
Keyword(s):  
Thermotoga Maritima ◽  
Binding Protein ◽  
Protein A ◽  
Hydrolysis Rate ◽  
Gtpase Activity ◽  
Gtp Binding Protein ◽  
Gene Encoding ◽  
Gtp Hydrolysis ◽  
Gtp Binding

ABSTRACT A gene encoding a putative GTP-binding protein, a TrmE homologue that is highly conserved in both prokaryotes and eukaryotes, was cloned from Thermotoga maritima, a hyperthermophilic bacterium.T. maritima TrmE was overexpressed in Escherichia coli and purified. TrmE has a GTPase activity but no ATPase activity. The GTPase activity can be competed with GTP, GDP, and dGTP but not with GMP, ATP, CTP, or UTP. Km andk cat at 70°C were 833 μM and 9.3 min−1, respectively. Our results indicate that TrmE is a GTP-binding protein with a very high intrinsic GTP hydrolysis rate. We also propose that TrmE homologues constitute a novel subfamily of the GTPase superfamily.

scholarly journals Structural Prediction and Mutational Analysis of Rv3906c Gene of Mycobacterium tuberculosis H37Rv to Determine Its Essentiality in Survival

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Md. Amjad Beg ◽  
Shivangi ◽  
Sonu Chand Thakur ◽  
Laxman S. Meena
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Mutational Analysis ◽  
Binding Protein ◽  
Protein A ◽  
Protein Motif ◽  
Gtp Binding Protein ◽  
Mycobacterium Tuberculosis H37rv ◽  
Gtp Binding ◽  
Extracellular Region ◽  
Binding Pockets

The emergence of tuberculosis is at the peak; therefore to station it at its lower level we hereby try bioinformatics approach against Mycobacterium tuberculosis [M. tuberculosis] pathogenesis. Rv3906c is a conserved hypothetical gene of M. tuberculosis and contains many GTP binding protein motif DXXG which demonstrate that this gene might be processed in a GTP binding or in GTP hydrolyzing manner. This gene shows interaction with its adjacent genes as well as pcnA which is a polymerase and localized in the extracellular region and found to be a soluble protein. Rv3906c has binding pockets for calcium atom at various positions which prove that calcium might have some role during the process of this gene. GTP binding protein motif DXXG is present in various positions and calcium binds at this site with a C-score of 0.25. Mutational analysis on this motif shows the large decrease of stability after mutation of aspartate residue with glycine. Stress conditions like pH and temperature also change stability of the protein. A decrease in stability at this position might play a role in inhibition of survival of the pathogen. These computational studies of this gene might be a successful step towards drug development against tuberculosis.

Cloning and chromosome assignment to 1q32 of a human cDNA (RAB7L1) encoding a small GTP-binding protein, a member of the RAS superfamily

1997 ◽  
Vol 77 (3-4) ◽  
pp. 261-263 ◽  
Author(s):  
F. Shimizu ◽  
T. Katagiri ◽  
M. Suzuki ◽  
T.K. Watanabe ◽  
S. Okuno ◽  
...  
Keyword(s):  
Binding Protein ◽  
Protein A ◽  
Gtp Binding Protein ◽  
Chromosome Assignment ◽  
Human Cdna ◽  
Gtp Binding ◽  
Ras Superfamily

scholarly journals Identification of a new GTP-binding protein. A Mr = 43,000 substrate for pertussis toxin.

1987 ◽  
Vol 262 (19) ◽  
pp. 9239-9245
Author(s):  
R Iyengar ◽  
K A Rich ◽  
J T Herberg ◽  
D Grenet ◽  
S Mumby ◽  
...  
Keyword(s):  
Pertussis Toxin ◽  
Binding Protein ◽  
Protein A ◽  
Gtp Binding Protein ◽  
Gtp Binding

Small GTP-binding Protein RalA Associates with Weibel-Palade Bodies in Endothelial Cells

1999 ◽  
Vol 82 (09) ◽  
pp. 1177-1181 ◽  
Author(s):  
Hubert de Leeuw ◽  
Pauline Wijers-Koster ◽  
Jan van Mourik ◽  
Jan Voorberg
Keyword(s):  
Endothelial Cells ◽  
Binding Proteins ◽  
Binding Protein ◽  
Control Release ◽  
Small Gtpase ◽  
Gtp Binding Protein ◽  
Two Dimensional Gel Electrophoresis ◽  
Gtp Binding Proteins ◽  
Dense Granules ◽  
Gtp Binding

SummaryIn endothelial cells von Willebrand factor (vWF) and P-selectin are stored in dense granules, so-called Weibel-Palade bodies. Upon stimulation of endothelial cells with a variety of agents including thrombin, these organelles fuse with the plasma membrane and release their content. Small GTP-binding proteins have been shown to control release from intracellular storage pools in a number of cells. In this study we have investigated whether small GTP-binding proteins are associated with Weibel-Palade bodies. We isolated Weibel-Palade bodies by centrifugation on two consecutive density gradients of Percoll. The dense fraction in which these subcellular organelles were highly enriched, was analysed by SDS-PAGE followed by GTP overlay. A distinct band with an apparent molecular weight of 28,000 was observed. Two-dimensional gel electrophoresis followed by GTP overlay revealed the presence of a single small GTP-binding protein with an isoelectric point of 7.1. A monoclonal antibody directed against RalA showed reactivity with the small GTP-binding protein present in subcellular fractions that contain Weibel-Palade bodies. The small GTPase RalA was previously identified on dense granules of platelets and on synaptic vesicles in nerve terminals. Our observations suggest that RalA serves a role in regulated exocytosis of Weibel-Palade bodies in endothelial cells.

Rap1b Association with the Platelet Cytoskeleton Occurs in the Absence of Glycoproteins IIb/IIIa

1998 ◽  
Vol 79 (04) ◽  
pp. 832-836 ◽  
Author(s):  
Thomas Fischer ◽  
Christina Duffy ◽  
Gilbert White
Keyword(s):  
Molecular Weight ◽  
Divalent Cation ◽  
Binding Proteins ◽  
Binding Protein ◽  
Platelet Membrane ◽  
Low Molecular Weight ◽  
Membrane Glycoproteins ◽  
Gtp Binding Protein ◽  
Gtp Binding Proteins ◽  
Gtp Binding

SummaryPlatelet membrane glycoproteins (GP) IIb/IIIa and rap1b, a 21 kDa GTP binding protein, associate with the triton-insoluble, activation-dependent platelet cytoskeleton with similar rates and divalent cation requirement. To examine the possibility that GPIIb/IIIa was required for rap1b association with the cytoskeleton, experiments were performed to determine if the two proteins were linked under various conditions. Chromatography of lysates from resting platelets on Sephacryl S-300 showed that GPIIb/IIIa and rap1b were well separated and distinct proteins. Immunoprecipitation of GPIIb/IIIa from lysates of resting platelets did not produce rap1b or other low molecular weight GTP binding proteins and immunoprecipitation of rap1b from lysates of resting platelets did not produce GPIIb/IIIa. Finally, rap1b was associated with the activation-dependent cytoskeleton of platelets from a patient with Glanzmann’s thrombasthenia who lacks surface expressed glycoproteins IIb and IIIa. Based on these findings, we conclude that no association between GPIIb/IIIa and rap1b is found in resting platelets and that rap1b association with the activation-dependent cytoskeleton is at least partly independent of GPIIb/IIIa.

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