A mutation at proline-115 in the A-factor receptor protein of Streptomyces griseus abolishes DNA-binding ability but not ligand-binding ability.
A-factor (2-isocapryloyl-3R-hydroxymethyl-gamma-butyrolactone) and its specific receptor protein (ArpA) are required for streptomycin production and aerial mycelium formation in Streptomyces griseus. A mutant strain HO1 that produced streptomycin and formed aerial mycelium and spores was derived from an A-factor-deficient mutant, S. griseus HH1. The phenotypes of mutant HO1 were found to result from a single amino acid replacement of ArpA; the proline residue at position 115 in the wild-type ArpA was replaced by serine, yielding mutant ArpA (P115S). The mutant ArpA (P115S) was still able to form a homodimer and possessed A-factor-binding ability but lost the ability to bind DNA. The properties of P115S suggest that ArpA consists of two independently functional domains, one for A-factor binding and one for DNA binding, and that proline-115 plays an important role in DNA binding. This is in agreement with the idea that A-factor binding to the COOH-terminal domain of ArpA causes a subtle conformational change of the distal NH2-terminal DNA-binding domain, resulting in dissociation of ArpA from DNA.
Onaka
H
H
Department of Biotechnology, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Bunkyo-ku, Japan.
Sugiyama
M
M
Horinouchi
S
S
D015107:4-Butyrolactone / Q000031:analogs & derivatives / Q000378:metabolism; D000818:Animals; D001426:Bacterial Proteins; D002417:Cattle; D004252:DNA Mutational Analysis; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D006133:Growth Substances; D008024:Ligands; D008970:Molecular Weight; D009154:Mutation; D011392:Proline / Q000502:physiology*; D012097:Repressor Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D013171:Spores, Bacterial; D013302:Streptomyces / Q000235:genetics / Q000254:growth & development* / Q000502:physiology; D013307:Streptomycin / Q000096:biosynthesis
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D006133:Growth Substances; D008024:Ligands; D012097:Repressor Proteins; C025035:A-factor (Streptomyces); D011392:Proline; D015107:4-Butyrolactone; D013307:Streptomycin