Biomaterial Database

Ribosome-independent GTPase activity of translation initiation factor IF2 and of its G-domain. 1991

M Severini, and R Spurio, and A La Teana, and C L Pon, and C O Gualerzi

Department of Biology, University of Camerino, Italy.

In the absence of ribosomes, Bacillus stearothermophilus translation initiation factor IF2 (Mr = 82 kDa) and its GTP-binding domain (i.e. the G-domain, Mr = 41 kDa) promote barely detectable hydrolysis of GTP. Upon addition of some aliphatic alcohols, however, the rate of nucleotide cleavage is substantially increased with both IF2 and G-domain, the highest stimulation being observed with 20% (v/v) ethanol. Under these conditions, the rates of ribosome-independent GTP hydrolysis with both IF2 and G-domain are approximately 30-fold lower than the corresponding rates obtained in the presence of ribosomes, while the Km for GTP is approximately the same in all cases. These results indicate that, as with the other two prokaryotic G proteins involved in translation (i.e. elongation factors EF-Tu and EF-G), also in the case of IF2, the GTPase catalytic center resides in the factor and, more specifically, in its G-domain.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D000431	Ethanol	A clear, colorless liquid rapidly absorbed from the gastrointestinal tract and distributed throughout the body. It has bactericidal activity and is used often as a topical disinfectant. It is widely used as a solvent and preservative in pharmaceutical preparations as well as serving as the primary ingredient in ALCOHOLIC BEVERAGES.	Alcohol, Ethyl,Absolute Alcohol,Grain Alcohol,Alcohol, Absolute,Alcohol, Grain,Ethyl Alcohol
D001411	Geobacillus stearothermophilus	A species of GRAM-POSITIVE ENDOSPORE-FORMING BACTERIA in the family BACILLACEAE, found in soil, hot springs, Arctic waters, ocean sediments, and spoiled food products.	Bacillus stearothermophilus,Bacillus thermoliquefaciens
D012270	Ribosomes	Multicomponent ribonucleoprotein structures found in the CYTOPLASM of all cells, and in MITOCHONDRIA, and PLASTIDS. They function in PROTEIN BIOSYNTHESIS via GENETIC TRANSLATION.	Ribosome
D015852	Eukaryotic Initiation Factor-2	Eukaryotic initiation factor of protein synthesis. In higher eukaryotes the factor consists of three subunits: alpha, beta, and gamma. As initiation proceeds, eIF-2 forms a ternary complex with Met-tRNAi and GTP.	EIF-2,Peptide Initiation Factor EIF-2,EIF-2 alpha,EIF-2 beta,EIF-2 gamma,EIF-2alpha,EIF-2beta,EIF-2gamma,EIF2,Eukaryotic Initiation Factor-2, alpha Subunit,Eukaryotic Initiation Factor-2, beta Subunit,Eukaryotic Initiation Factor-2, gamma Subunit,Eukaryotic Peptide Initiation Factor-2,EIF 2,EIF 2 alpha,EIF 2 beta,EIF 2 gamma,EIF 2alpha,EIF 2beta,EIF 2gamma,Eukaryotic Initiation Factor 2,Eukaryotic Initiation Factor 2, alpha Subunit,Eukaryotic Initiation Factor 2, beta Subunit,Eukaryotic Initiation Factor 2, gamma Subunit,Eukaryotic Peptide Initiation Factor 2,Initiation Factor-2, Eukaryotic,Peptide Initiation Factor EIF 2
D019204	GTP-Binding Proteins	Regulatory proteins that act as molecular switches. They control a wide range of biological processes including: receptor signaling, intracellular signal transduction pathways, and protein synthesis. Their activity is regulated by factors that control their ability to bind to and hydrolyze GTP to GDP. EC 3.6.1.-.	G-Proteins,GTP-Regulatory Proteins,Guanine Nucleotide Regulatory Proteins,G-Protein,GTP-Binding Protein,GTP-Regulatory Protein,Guanine Nucleotide Coupling Protein,G Protein,G Proteins,GTP Binding Protein,GTP Binding Proteins,GTP Regulatory Protein,GTP Regulatory Proteins,Protein, GTP-Binding,Protein, GTP-Regulatory,Proteins, GTP-Binding,Proteins, GTP-Regulatory
D020558	GTP Phosphohydrolases	Enzymes that hydrolyze GTP to GDP. EC 3.6.1.-.	GTPase,GTPases,Guanosine Triphosphate Phosphohydrolases,Guanosinetriphosphatases,GTP Phosphohydrolase,Phosphohydrolase, GTP,Phosphohydrolases, GTP,Phosphohydrolases, Guanosine Triphosphate,Triphosphate Phosphohydrolases, Guanosine