Biomaterial Database

Insertion of newly synthesized proteins into the outer membrane of Escherichia coli. 1978

L de Leij, and J Kingma, and B Witholt

The insertion of newly synthesized proteins into the outer membrane of Escherichia coli has been examined. The results show that there is no precurser pool of outer membrane proteins in the cytoplasmic membrane because first, the incorporation of a [35S]methionine pulse into outer membrane proteins completely parallels its incorporation into cytoplasmic membrane proteins, and second, under optimal isolation conditions, no outer membrane proteins are found in the cytoplasmic membrane, even when the membranes are analysed after being labeled for only 15 s. The [35S]methionine present in the outer membrane after a pulse of 15 s was found in protein fragments of varying sizes rather than in specific outer membrane proteins. This label could however be chased into specific proteins within 30--120 s, depending on the size of the protein, indicating that although unfinished protein fragments were present in the outer membrane, they were completed by subsequent chain elongation. Thus, outer membrane proteins are inserted into the outer membrane while still attached to ribosomes. Since ribosomes which are linked to the cell envelope by nascent polypeptide chains are stationary, the mRNA which is being translated by these ribosomes moves along the inner cell surface.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008565	Membrane Proteins	Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.	Cell Membrane Protein,Cell Membrane Proteins,Cell Surface Protein,Cell Surface Proteins,Integral Membrane Proteins,Membrane-Associated Protein,Surface Protein,Surface Proteins,Integral Membrane Protein,Membrane Protein,Membrane-Associated Proteins,Membrane Associated Protein,Membrane Associated Proteins,Membrane Protein, Cell,Membrane Protein, Integral,Membrane Proteins, Integral,Protein, Cell Membrane,Protein, Cell Surface,Protein, Integral Membrane,Protein, Membrane,Protein, Membrane-Associated,Protein, Surface,Proteins, Cell Membrane,Proteins, Cell Surface,Proteins, Integral Membrane,Proteins, Membrane,Proteins, Membrane-Associated,Proteins, Surface,Surface Protein, Cell
D008715	Methionine	A sulfur-containing essential L-amino acid that is important in many body functions.	L-Methionine,Liquimeth,Methionine, L-Isomer,Pedameth,L-Isomer Methionine,Methionine, L Isomer
D002458	Cell Fractionation	Techniques to partition various components of the cell into SUBCELLULAR FRACTIONS.	Cell Fractionations,Fractionation, Cell,Fractionations, Cell
D002462	Cell Membrane	The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.	Plasma Membrane,Cytoplasmic Membrane,Cell Membranes,Cytoplasmic Membranes,Membrane, Cell,Membrane, Cytoplasmic,Membrane, Plasma,Membranes, Cell,Membranes, Cytoplasmic,Membranes, Plasma,Plasma Membranes
D002701	Chloramphenicol	An antibiotic first isolated from cultures of Streptomyces venequelae in 1947 but now produced synthetically. It has a relatively simple structure and was the first broad-spectrum antibiotic to be discovered. It acts by interfering with bacterial protein synthesis and is mainly bacteriostatic. (From Martindale, The Extra Pharmacopoeia, 29th ed, p106)	Cloranfenicol,Kloramfenikol,Levomycetin,Amphenicol,Amphenicols,Chlornitromycin,Chlorocid,Chloromycetin,Detreomycin,Ophthochlor,Syntomycin
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
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