From substrate specificity to promiscuity: hybrid ABC transporters for osmoprotectants

摘要: Summary The ABC-transporters OpuB and OpuC from Bacillus subtilis function as osmoprotectant import systems. Their structural genes have most likely evolved through a duplication event but the two transporters are remarkably different in their substrate profile. possesses narrow specificity, while is promiscuous. We assessed functionality of hybrids between these by reciprocally exchanging coding regions for OpuBC OpuCC substrate-binding proteins corresponding opuB opuC operons. Substantiating critical role binding protein setting specificity ABC transporters, OpuB::OpuCC turned into promiscuous system, OpuC::OpuBC now exhibited specificity. Both hybrid possessed high affinity substrates transport capacity system was moderate due to synthesis only low amounts xenogenetic protein. Suppressor mutations causing single amino acid substitutions GbsR repressor controlling choline glycine betaine biosynthesis pathway greatly improved OpuB::OpuCC-mediated compatible solute transcriptional up-regulation opuB::opuCC operon. Collectively, we demonstrate first time that one can synthetically switch given transporter combining its core components with ligand-binding This article protected copyright. All rights reserved.