title: Sequence analyses of cyanobacterial bicarbonate transporters and their homologues.
abstract: The primary HCO3- uptake system in the cyanobacterium Synecocystis is the Na+-dependent transporter SbtA. SbtA and its homologues were identified and shown to display a common topology of ten transmembrane segments (TMSs). These proved to have arisen by an intragenic duplication event from an ancestral gene encoding a five TMS protein product. A region of SbtA shows sufficient similarity to 10 TMS ABC-type integral membrane transport proteins to suggest a common origin. Phylogenetic analyses of the SbtA family revealed two clusters of cyanobacterial homologues with all non-cyanobacterial family members outside of these two clusters. The tree topology suggests that SbtA family members display multiple transport functions.
authors.affiliation: Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093-0116, USA.
authors.forename: Torsten
authors.initials: T
authors.lastname: von Rozycki
authors.forename: Mark A
authors.initials: MA
authors.lastname: Schultzel
authors.forename: Milton H
authors.initials: MH
authors.lastname: Saier
mesh_terms: D000595:Amino Acid Sequence; D001639:Bicarbonates / Q000378:metabolism*; D001692:Biological Transport; D017124:Conserved Sequence; D000458:Cyanobacteria / Q000235:genetics* / Q000378:metabolism; D006090:Gram-Negative Bacteria / Q000378:metabolism; D006094:Gram-Positive Bacteria / Q000378:metabolism; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D027982:Sodium-Bicarbonate Symporters / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
chemical_list: D001639:Bicarbonates; D027982:Sodium-Bicarbonate Symporters