Biomaterial Database

Accumulation of free ribosomal proteins S1, L7, and L12 in Escherichia coli. 1976

S Ramagopal

The total content of free ribosomal proteins in the cells of Escherichia coli was determined to study the nature of intracellular accumulation during growth. Labeled ribosomes and post-ribosomal supernatant were prepared from exponentially growing and stationary-phase cultures. The fraction of free ribosomal protein in the supernatant was estimated by resolving both the acidic and basic proteins separately with two different techniques of two-dimensional gel electrophoresis. Free ribosomal proteins in the cell sap were identified on the basis of coelectrophoresis with authentic ribosomal protein markers, molecular weights and amino acid composition. Among the acidic proteins, S1, L7, and L12 were identified and examined in detail. All three proteins accumulated to significant levels in these cultures. Stationary-phase cells contained 2-4 times more free S1, L7, and L12 than midlogarithmic phase cells. Moreover, free S1, L7, and L12 and ribosome-bound forms were stable during exponential and post-exponential growth of cultures. At this growth transition, non-ribosomal proteins in the supernatant and those associated with the ribosomes showed different characteristics of accumulation. The ratio of L12:L7 in the supernatant did not exhibit a remarkable shift during the growth cycle like the ratio of L12:L7 in ribosomes. In addition, free L12 in the supernatant was not acetylated, although there was a rapid acetylation in the cells.

UI	MeSH Term	Description	Entries
D002455	Cell Division	The fission of a CELL. It includes CYTOKINESIS, when the CYTOPLASM of a cell is divided, and CELL NUCLEUS DIVISION.	M Phase,Cell Division Phase,Cell Divisions,Division Phase, Cell,Division, Cell,Divisions, Cell,M Phases,Phase, Cell Division,Phase, M,Phases, M
D003600	Cytosol	Intracellular fluid from the cytoplasm after removal of ORGANELLES and other insoluble cytoplasmic components.	Cytosols
D004591	Electrophoresis, Polyacrylamide Gel	Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.	Polyacrylamide Gel Electrophoresis,SDS-PAGE,Sodium Dodecyl Sulfate-PAGE,Gel Electrophoresis, Polyacrylamide,SDS PAGE,Sodium Dodecyl Sulfate PAGE,Sodium Dodecyl Sulfate-PAGEs
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
D000596	Amino Acids	Organic compounds that generally contain an amino (-NH2) and a carboxyl (-COOH) group. Twenty alpha-amino acids are the subunits which are polymerized to form proteins.	Amino Acid,Acid, Amino,Acids, Amino
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
D012269	Ribosomal Proteins	Proteins found in ribosomes. They are believed to have a catalytic function in reconstituting biologically active ribosomal subunits.	Proteins, Ribosomal,Ribosomal Protein,Protein, Ribosomal
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