tailieunhanh - Báo cáo khoa học: A novel ATP-binding cassette transporter is responsible for resistance to viologen herbicides in the cyanobacterium Synechocystis sp. PCC 6803

The charged quaternary ammonium compounds – methyl, ethyl and benzyl viologens – generate reactive oxygen species in photosynthetic cells. Three independent methyl viologen-resistant spontaneous mutants of Synechocys-tis sp. PCC 6803 were identified, in which the conserved R115 residue of the Slr1174 protein was replaced with G115, L115 and C115. The Slr1174 protein of the DUF990 family is related to the permease subunit of an ABC-2-type transporter and its R115 mutation was found to be solely responsible for the observed methyl viologen resistance. . | ỊFEBS Journal A novel ATP-binding cassette transporter is responsible for resistance to viologen herbicides in the cyanobacterium Synechocystis sp. PCC 6803 Jana Prosecka1 2 Artem V. Orlov3 Yuri S. Fantin3 Vladislav V. Zinchenko3 Michael M. Babykin4 and Martin Tichy1 2 1 Department of Autotrophic Microorganisms Institute of Microbiology Trebon Czech Republic 2 Institute of PhysicalBiology University of South Bohemia Nove Hrady Czech Republic 3 Department of Genetics Moscow State University Russia 4 InternationalBiotechnologicalCentre Moscow State University Russia Keywords ABC-type transporter cyanobacteria DUF990 family proteins oxidative stress viologen herbicide resistance Correspondence M. Tichy Laboratory of Photosynthesis Institute of Microbiology Opatovicky mlyn Trebon 379 81 Czech Republic Fax 400 384 340415 Tel 400 384 340433 E-mail tichym@ Received 23 January 2009 revised 18 May 2009 accepted 22 May 2009 doi The charged quaternary ammonium compounds - methyl ethyl and benzyl viologens - generate reactive oxygen species in photosynthetic cells. Three independent methyl viologen-resistant spontaneous mutants of Synechocys-tis sp. PCC 6803 were identified in which the conserved R115 residue of the Slr1174 protein was replaced with G115 L115 and C115. The Slr1174 protein of the DUF990 family is related to the permease subunit of an ABC-2-type transporter and its R115 mutation was found to be solely responsible for the observed methyl viologen resistance. Bioinformatic analysis showed that in various bacterial genomes two genes encoding another permease subunit and the ATPase component of an ATP-binding cassette transporter form putative operons with slr1174 orthologs suggesting that the protein products of these genes may form functional transporters. The corresponding genes in Synechocystis sp. PCC 6803 . slr0610 for the permease and slr1901 for the ATPase did not form such an operon. However insertional .