Bavoil P, Hofnung M, Nikaido H
J Biol Chem. 1980 Sep 25;255(18):8366-9.
The maltose transport system of Escherichia coli contains at least five components, three of which, i.e. the products of lamB, malE, and malF genes, have so far been identified as constituents of the outer membrane, periplasmic space, and cytoplasmic membrane, respectively. We identified another component, a cytoplasmic membrane protein of an apparent molecular weight of 43,000, as the product of the malK gene on the basis of polyacrylamide gel electrophoretic analysis of various mutants and suppressed strains and by the incorporation of extra tyrosine residue into this proten in malK amber mutants containing the suppressor Su3+ allele. The transport of maltose thus appears to require at least two proteins associated with the cytoplasmic membrane.
大肠杆菌的麦芽糖转运系统至少包含五个组分，其中三个，即lamB、malE和malF基因的产物，目前已分别被鉴定为外膜、周质空间和细胞质膜的组成成分。基于对各种突变体和抑制菌株的聚丙烯酰胺凝胶电泳分析，以及通过在含有抑制基因Su3 + 等位基因的malK琥珀突变体中将额外的酪氨酸残基掺入该蛋白中，我们鉴定出另一个组分，一种表观分子量为43,000的细胞质膜蛋白，为malK基因的产物。因此，麦芽糖的转运似乎至少需要两种与细胞质膜相关的蛋白质。
