This family includes both ResB and cytochrome c biogenesis proteins [1,2]. Mutations in ResB indicate that they are essential for growth [1]. ResB is predicted to be a transmembrane protein [1].

1: Genes required for cytochrome c synthesis in Bacillus subtilis. Le Brun NE, Bengtsson J, Hederstedt L; Mol Microbiol 2000;36:638-650. PMID:10844653

2: Regulators of aerobic and anaerobic respiration in Bacillus subtilis. Sun G, Sharkova E, Chesnut R, Birkey S, Duggan MF, Sorokin A, Pujic P, Ehrlich SD, Hulett FM; J Bacteriol 1996;178:1374-1385. PMID:8631715