Trehalose monomycolate (TMM) represents an essential element of the mycobacterial envelope. While synthesized in the cytoplasm, TMM is transported across the inner membrane by MmpL3 but, little is known regarding the MmpL3 partners involved in this process. Recently, the TMM transport factor A (TtfA) was found to form a complex with MmpL3 and to participate in TMM transport, although its biological role remains to be established. Herein, we report the crystal structure of the Mycobacterium smegmatis TtfA core domain. The phylogenetic distribution of TtfA homologues in non-mycolate containing bacteria suggests that TtfA may exert additional functions.

中文翻译：

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分枝杆菌海藻糖单霉菌酸酯转运因子A TtfA的晶体结构显示出非典型折叠。

海藻糖单霉菌酸酯（TMM）代表了分枝杆菌包膜的必要元素。当在细胞质中合成时，TMM被MmpL3转运穿过内膜，但对于参与该过程的MmpL3伴侣知之甚少。最近，尽管有待确定其生物学作用，但发现TMM转运因子A（TtfA）与MmpL3形成复合物并参与TMM转运。在这里，我们报告耻垢分枝杆菌TtfA核心域的晶体结构。TtfA同源物在不含霉菌的细菌中的系统发育分布表明，TtfA可能发挥其他功能。