3.A.1.1.51
Maltose - maltoheptaose transporter, MalEFGK.  MalEF is a R-M fusion protein with the MalE domain N-terminal and the MalF domain C-terminal. The protein, of 733 aas, has 8 TMSs, one N-terminal to MalE (a signal sequence for export of the MalE domain to the periplasm), an extra TMS at the N-terminus to bring the N-terminus to the periplasmic side of the inner membrane, and then the usual 6 TMSs observed for many ABC membrane proteins.  MalG (M, 272 aas, 6 TMSs) and MalK (C, 374 aas) are of normal size and composition. While MalE of E. coli was able to additionally increase ATPase activity of MalFGK₂ in vitro, the isolated MalE domain of B. bacteriovorus failed to stimulate the E. coli system (Licht et al. 2018). The adjacent genes are an α-amylase (Q6MNM3) and a glucokinase (Q6MNM4).