9.B.8 The DUF2157 (DUF2157) Family
The DUF2157 family consists of many proteins of 10, 12 and 14 TMSs with no extended hydrophilic domains, but some homologues have 19, 21 or 22 TMSs. They occur largely in bacteria although archaeal homologues have been detected. Some homologues are annotated as Brp/Blh family β-carotene 15,15' monoxygenase (see TC# 9.B.8.1.4). Others are annotated 'carotenoid bisynthesis protein'. These proteins may be glycosyltransferases distantly related to those of TC family 9.B.142.