Cloning and DNA sequence analysis of the mercury resistance genes of Streptomyces lividans.
A broad-spectrum mercury resistance locus (mer) from a spontaneous chloramphenicol-sensitive (Cms), arginine auxotrophic (Arg-) mutant of Streptomyces lividans 1326 was isolated on a 6 kb DNA fragment by shotgun cloning into the mercury-sensitive derivative S. lividans TK64 using the vector pIJ702. The mer genes form part of a very large amplifiable DNA sequence present in S. lividans 1326. This element was amplified to about 20 copies per chromosome in the Cms Arg- mutant and was missing from strains like S. lividans TK64, cured for the plasmid SLP3. DNA sequence analysis of a 5 kb region encompassing the whole region required for broad-spectrum mercury resistance revealed six open reading frames (ORFs) transcribed in opposite directions from a common intercistronic region. The protein sequences predicted from the two ORFs transcribed in one direction showed a high degree of similarity to mercuric reductase and organomercurial lyase from other gram-negative and gram-positive sources. Few, if any, similarities were found between the predicted polypeptide sequences of the other four ORFs and other known proteins.
Sedlmeier
R
R
Institut für Genetik und Mikrobiologie, Universität München, FRG.
Altenbuchner
J
J
D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D004269:DNA, Bacterial; D004352:Drug Resistance, Microbial / Q000235:genetics; D005798:Genes, Bacterial; D008628:Mercury / Q000494:pharmacology*; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D013302:Streptomyces / Q000187:drug effects / Q000235:genetics*
D004269:DNA, Bacterial; D008628:Mercury