title: Polypeptide chain initiation in E. coli: isolation of homogeneous initiation factor E2 and its relation to ribosomal proteins.
abstract: Previous work has shown that F(2), one of several ribosomal factors involved in polypeptide chain initiation, functions in the binding of formylmethionyl-transfer RNA (fMet approximately tRNA(f)) to a messenger RNA-ribosome complex. F(2) was isolated from 1.0 M ammonium chloride washes of E. coli Q13 ribosomes as a protein homogeneous on polyacrylamide gel electrophoresis at both pH 4.5 and 7.8. Its molecular weight is approximately 80,000. Comparison of electrophoretic patterns of ribosomal proteins from NH(4)Cl-washed and unwashed ribosomes and F(2), at pH 4.5, shows that F(2) corresponds to the slowest-moving component of the proteins derived from unwashed ribosomes. This component is missing from the NH(4)Cl-washed ribosomes. The activity of F(2) is stimulated by two additional factors, initiation factor F(1) and a factor(s) present in a narrow ammonium sulfate fraction of the ribosomal NH(4)Cl wash. The nature of the latter is unknown.
mesh_terms: D000643:Ammonium Chloride; D001426:Bacterial Proteins / Q000096:biosynthesis; D002845:Chromatography; D004589:Electrophoresis, Disc; D004926:Escherichia coli; D008970:Molecular Weight; D010455:Peptides; D012329:RNA, Bacterial; D012333:RNA, Messenger; D012343:RNA, Transfer; D012270:Ribosomes
chemical_list: D001426:Bacterial Proteins; D010455:Peptides; D012329:RNA, Bacterial; D012333:RNA, Messenger; D000643:Ammonium Chloride; D012343:RNA, Transfer