Biomaterial Database

Role of guanine nucleotides in protein synthesis. Elongation factor G and guanosine 5'-triphosphate,3'-diphosphate. 1973

E Hamel, and M Cashel

The possible role of guanosine 5'-triphosphate,3'-diphosphate (pppGpp) in protein synthesis by Escherichia coli ribosomes and protein factors was examined. Although pppGpp could effectively substitute for GTP in reactions catalyzed by initiation factor 2 (ribosomal binding of fMet-tRNA and formation of N-formylmethionylpuromycin) and elongation factor T (ribosomal binding of Phe-tRNA and formation of dipeptidyl-tRNA), pppGpp poorly supported polyphenylalanine synthesis. The interaction of elongation factor G with pppGpp was, therefore, examined in detail. The nucleotide was found to be almost without activity in the translocation reaction, as measured by formation of N-acetylphenylalanyl-phenylalanylpuromycin. Nevertheless, the rate of the catalytic hydrolysis of pppGpp to guanosine 5'-diphosphate,3'-diphosphate by elongation factor G and ribosomes was about 30% of the rate of hydrolysis of GTP, a rate of hydrolysis that significantly exceeded the rate of translocation with GTP. Moreover, the rates of the fusidic acid-dependent, elongation factor G-dependent binding of pppGpp and ppGpp to ribosomes were about 75 to 85% the rates of GTP and GDP binding, respectively. We also found that dGTP could substitute for GTP in all reactions examined.

UI	MeSH Term	Description	Entries
D010442	Peptide Chain Initiation, Translational	A process of GENETIC TRANSLATION whereby the formation of a peptide chain is started. It includes assembly of the RIBOSOME components, the MESSENGER RNA coding for the polypeptide to be made, INITIATOR TRNA, and PEPTIDE INITIATION FACTORS; and placement of the first amino acid in the peptide chain. The details and components of this process are unique for prokaryotic protein biosynthesis and eukaryotic protein biosynthesis.	Chain Initiation, Peptide, Translational,Protein Biosynthesis Initiation,Protein Chain Initiation, Translational,Protein Translation Initiation,Translation Initiation, Genetic,Translation Initiation, Protein,Translational Initiation, Protein,Translational Peptide Chain Initiation,Biosynthesis Initiation, Protein,Genetic Translation Initiation,Initiation, Genetic Translation,Initiation, Protein Biosynthesis,Initiation, Protein Translation,Initiation, Protein Translational,Protein Translational Initiation
D010445	Peptide Elongation Factors	Protein factors uniquely required during the elongation phase of protein synthesis.	Elongation Factor,Elongation Factors, Peptide,Factor, Elongation,Factors, Peptide Elongation
D010452	Peptide Biosynthesis	The production of PEPTIDES or PROTEINS by the constituents of a living organism. The biosynthesis of proteins on RIBOSOMES following an RNA template is termed translation (TRANSLATION, GENETIC). There are other, non-ribosomal peptide biosynthesis (PEPTIDE BIOSYNTHESIS, NUCLEIC ACID-INDEPENDENT) mechanisms carried out by PEPTIDE SYNTHASES and PEPTIDYLTRANSFERASES. Further modifications of peptide chains yield functional peptide and protein molecules.	Biosynthesis, Peptide
D010649	Phenylalanine	An essential aromatic amino acid that is a precursor of MELANIN; DOPAMINE; noradrenalin (NOREPINEPHRINE), and THYROXINE.	Endorphenyl,L-Phenylalanine,Phenylalanine, L-Isomer,L-Isomer Phenylalanine,Phenylalanine, L Isomer
D010761	Phosphorus Radioisotopes	Unstable isotopes of phosphorus that decay or disintegrate emitting radiation. P atoms with atomic weights 28-34 except 31 are radioactive phosphorus isotopes.	Radioisotopes, Phosphorus
D004926	Escherichia coli	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.	Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli
D006150	Guanine Nucleotides		Guanine Nucleotide,Guanosine Phosphates,Nucleotide, Guanine,Nucleotides, Guanine,Phosphates, Guanosine
D006160	Guanosine Triphosphate	Guanosine 5'-(tetrahydrogen triphosphate). A guanine nucleotide containing three phosphate groups esterified to the sugar moiety.	GTP,Triphosphate, Guanosine
D006868	Hydrolysis	The process of cleaving a chemical compound by the addition of a molecule of water.
D001426	Bacterial Proteins	Proteins found in any species of bacterium.	Bacterial Gene Products,Bacterial Gene Proteins,Gene Products, Bacterial,Bacterial Gene Product,Bacterial Gene Protein,Bacterial Protein,Gene Product, Bacterial,Gene Protein, Bacterial,Gene Proteins, Bacterial,Protein, Bacterial,Proteins, Bacterial