This family consists of several bacterial proteins of unknown function, however members have been suggested to be an accessory protein for sulfite reduction. This is based on the observation that they strongly cofit with various genes in the sulfate assimilation pathway in various Pseudomonas as well as in Marinobacter adhaerens HP15 and C. basilensis 4G11 (see Supplementary note 5 in [1].)

1: Mutant phenotypes for thousands of bacterial genes of unknown function. Price MN, Wetmore KM, Waters RJ, Callaghan M, Ray J, Liu H, Kuehl JV, Melnyk RA, Lamson JS, Suh Y, Carlson HK, Esquivel Z, Sadeeshkumar H, Chakraborty R, Zane GM, Rubin BE, Wall JD, Visel A, Bristow J, Blow MJ, Arkin AP, Deutschbauer AM; Nature. 2018;557:503-509. PMID:29769716