title: Acetohydroxy acid synthase isoenzymes of Escherichia coli K-12: a trans-acting regulatory locus of ilvHI gene expression.
abstract: We isolated an Escherichia coli K-12 regulatory mutation affecting the acetohydroxy acid synthase III isoenzyme. This mutation was found to lie outside the structural genes ilvHI for this isoenzyme and was designated lrs-1. A strain carrying this mutation was found to be altered in the leucine-mediated control of ilvHI mRNA and acetohydroxy acid synthase III synthesis observed in the isogenic lrs+ strain. These alterations appeared to be a consequence of a reduced intracellular concentration of a single one of five tRNALeu isoaccepting species.
mesh_terms: D000095:Acetolactate Synthase / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics*; D005786:Gene Expression Regulation; D005799:Genes, Dominant; D005809:Genes, Regulator; D007527:Isoenzymes / Q000235:genetics*; D007532:Isoleucine / Q000096:biosynthesis; D007930:Leucine / Q000096:biosynthesis; D009154:Mutation; D007652:Oxo-Acid-Lyases / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis; D012346:RNA, Transfer, Amino Acyl / Q000378:metabolism; D014633:Valine / Q000096:biosynthesis
chemical_list: D007527:Isoenzymes; D012333:RNA, Messenger; D012346:RNA, Transfer, Amino Acyl; D007532:Isoleucine; D000095:Acetolactate Synthase; D007652:Oxo-Acid-Lyases; D007930:Leucine; D014633:Valine