Homologs of Rru_A1636 from Rhodospirillum rubrum S1H
NADH-ubiquinone oxidoreductase, chain 4L (NCBI)
SEED: PH adaptation potassium efflux system protein C; sodium- potassium/hydrogen antiporter subunit C
KEGG: multicomponent Na+:H+ antiporter subunit C
39 hits from BLASTp (E < 0.01)
Or try PaperBLAST, fast.genomics, the ENIGMA genome browser, or the comparative fitness browser