Identification and characterization of hmr19 gene encoding a multidrug resistance efflux protein from Streptomyces hygroscopicus subsp. yingchengensis strain 10-22.
The hmr19 gene was cloned from Streptomyces hygroscopicus subsp. yingchengensis strain 10-22, a bacterium strain producing agricultural antibiotics. Sequence similarity comparison indicates that hmr19 gene may encode a predicted protein with 14 putative transmembrane alpha-helical spanners, belonging to the drug:H(+) antiporter-2 family of the major facilitator superfamily. The expression of hmr19 in the mycelium of strain 10-22 was detected by Western blotting analysis. Gene replacement technology was employed to construct an hmr19 disruption mutant. The growth inhibition test against different antibiotics indicated that the mutant strain was 5-20 fold more susceptible to tetracycline, vancomycin and mitomycin C than the parental wild type strain. The mutant took up tetracycline much faster and accumulated more antibiotics than the wild type strain 10-22. While with the addition of an energy uncoupler, carbonyl cyanide m-chlorophenylhydrazone, the characteristics of the accumulation of [(3)H]tetracycline in these two strains were almost the same. It was thus concluded that hmr19 encoded a multidrug resistance efflux protein.
Shanghai Research Center of Biotechnology, Shanghai Institute for Biological Sciences, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Shanghai 200233, China.
Lei
L
Qin
Heng-An
HA
Wang
Zhong-Qin
ZQ
Wu
Xiao-Feng
XF
Zhang
Mei-Lei
ML
Jin
Zi-Xin
ZX
Deng
Guo-Ping
GP
Zhao
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics; D004734:Energy Metabolism; D017353:Gene Deletion; D005798:Genes, Bacterial; D019450:Genes, MDR; D008969:Molecular Sequence Data; D010641:Phenotype; D017386:Sequence Homology, Amino Acid; D013302:Streptomyces / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D013752:Tetracycline / Q000378:metabolism
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D013752:Tetracycline