Characterization of the ABC Transporter Gene slr1045 Involved in Acid-stress Tolerance of Synechocystis sp. PCC 6803

Abstract

The ATP-binding cassette (ABC) transporters form one of the largest known-protein families; these are widespread in bacteria, archaea, and eukaryotes and are encoded in the largest set of paralogous genes. In the Synechocystis sp. PCC6803 genome, over 50 ABC transporter-related genes have been detected by genome sequence analysis. Some of these have been identified as Na+/H+, iron, phosphate, polysaccharide, and CO2 transporters. The substrates of many other ABC transporters are still unknown. To identify ABC transporters involved in acid tolerance, deletion mutants of other substrate-unknown ABC transporter genes were screened for their acid-stress sensitivities in a low-pH medium. A mutant of slr1045 was found to be more sensitive to acid stress than wild-type cells. The abundance of expression of the genes was analyzed under various stress conditions by quantitative real time reverse transcriptase-polymerase chain reaction.