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9.B.28 The Putative Protease Component of the MusEFGKI ABC Transporter (MusI) Family

A maltose transporter, MusEFGKI of Corynebacterium glutamicum is believed to include an extra subunit designated MusI.  All five genes (musEFGKI) have been reported to be essential for uptake activity (Henrich et al. 2013).  The musI gene product is of 215 aas with 5 TMSs and comprises the founding member of a distinct family of uncharacterized protein in this TC family (MusI; 9.B.28).  However members of the family can have 4 - 7 TMSs.  Family members are found in bacteria, archaea and eukaryotes and show sequence and topological similarity to members of the rhomboid (TC# 9.B.104) and CAAX2 (9.B.2) protease families.  Some members of the MusI family have therefore been transferred to the Rhomboid Protease Family (9.B.104). Proteins of TC family 9.B.28 (particularly 9.B.325.2.6 and 7) show sequence similarity with one of the members of TC family 9.B.325 (9.B.325.1.2) which unlike other members of the 9.B.325 family have either 5 TMS alone, or 10 TMSs with a 5 TMS repeat unit.
This family belongs to the: MusI (MusI) Superfamily.

References associated with 9.B.28 family:

Henrich, A., N. Kuhlmann, A.W. Eck, R. Krämer, and G.M. Seibold. (2013). Maltose uptake by the novel ABC transport system MusEFGK2I causes increased expression of ptsG in Corynebacterium glutamicum. J. Bacteriol. 195: 2573-2584. 23543710