9.B.98 The DUF95 (DUF95) Family
The DUF95 family consists of proteins that exhibit 4, 5 or 6 TMSs. They usually contain about 200 aas but can have N-terminal hydrophilic extensions of >100 aas. Members are found in archaea and bacteria. DUF95 domains are found in a few ABC transport systems such as 3.A.1.112.7 where the system may have an extra 4 TMS subunit. Another ABC transport system having this domain is the 18 TMS protein (3.A.1.144.4) which has a 6 + 6 + 6 arrangement, and the last 6 TMSs correspond to the DUF95 domain. The transporter under TC# 9.B.98.1.4 probably consists of two membrane proteins of 12 (CirB) and 4 (CirC) TMSs as well as an ATP-hydrolyzing subunit (CirD). It has been suggested that DUF95 proteins are auxilary subunits of bacteriocin ABC exporters (van Belkum et al., 2011). These proteins may be distantly related to TatC (2.A.64).