Phylogeny and hydropathy of StbA from different microorganisms. The blue boxes indicate sequences belonging to the cyanobacteria. The dots on the branches are bootstrap values between 50% and 75% (open dots) or between 75% and 100% (closed dots) The scale bar indicated 10% sequence difference. The sequence of Thioalkalivibrio sp. K90mix is indicated in bold. Hydropathy profiles were made for the StbA protein sequences of Synechocystis sp. PCC6803 and Thioalkalivibrio sp. K90mix to indicate transmembrane spanning domains.