Heuzenroeder M W, Reeves P
J Bacteriol. 1980 Feb;141(2):431-5. doi: 10.1128/jb.141.2.431-435.1980.
ompB mutants of Escherichia coli K-12 are markedly deficient in porin in their outer membrane. This results in a decreased rate of uptake for many substrates: the maltose pore (lambda receptor) can in some circumstances, in the absence of the periplasmic maltose-binding protein, compensate for the consequent defects in permeability to lactose, mannitol, glycylglycyl-L-valine, and tri-L-ornithine. It is postulated that the maltose-binding protein associates with the maltose pore and confers on it the specificity for maltose, and that the absence of the maltose-binding protein leaves the pore open and results in enhanced transmembrane diffusion of molecules other than maltose. This paper presents evidence to support this hypothesis.
大肠杆菌K-12的ompB突变体在外膜中孔蛋白明显缺乏。这导致许多底物的摄取速率降低：在某些情况下，麦芽糖孔（λ受体）在没有周质麦芽糖结合蛋白的情况下，可以弥补随之而来的对乳糖、甘露醇、甘氨酰甘氨酰-L-缬氨酸和三-L-鸟氨酸通透性的缺陷。据推测，麦芽糖结合蛋白与麦芽糖孔结合并赋予其对麦芽糖的特异性，而麦芽糖结合蛋白的缺失会使孔开放，导致除麦芽糖以外的分子跨膜扩散增强。本文提供了支持这一假设的证据。
