具有改变孔道特性的OmpC孔蛋白突变体的分离与鉴定
Isolation and characterization of OmpC porin mutants with altered pore properties.
作者信息
Misra R, Benson S A
机构信息
Department of Molecular Biology, Princeton University, New Jersey 08544.
出版信息
J Bacteriol. 1988 Feb;170(2):528-33. doi: 10.1128/jb.170.2.528-533.1988.
The LamB protein is normally required for the uptake of maltodextrins. Starting with a LamB- OmpF- strain, we have isolated mutants that will grow on maltodextrins. The mutation conferring the Dex+ phenotype in the majority of these mutants has been mapped to the ompC locus. These mutants, unlike LamB- OmpF- strains, grew on maltotriose and maltotetraose, but not on maltopentaose, and showed a significantly higher rate of [14C]maltose uptake than the parent strain did. In addition, these mutants showed increased sensitivity to certain beta-lactam antibiotics and sodium dodecyl sulfate, but did not exhibit an increase in sensitivity to other antibiotics and detergents. The nucleotide sequence of these mutants has been determined. In all cases, residue 74 (arginine) of the mature OmpC protein was affected. The results suggest that this region of the OmpC protein is involved in the pore domain and that the alterations lead to an increased pore size.
麦芽糖糊精的摄取通常需要LamB蛋白。从LamB - OmpF -菌株开始，我们分离出了能在麦芽糖糊精上生长的突变体。在这些突变体中，大多数赋予Dex +表型的突变已被定位到ompC基因座。与LamB - OmpF -菌株不同，这些突变体能在麦芽三糖和麦芽四糖上生长，但不能在麦芽五糖上生长，并且显示出比亲本菌株更高的[14C]麦芽糖摄取率。此外，这些突变体对某些β -内酰胺抗生素和十二烷基硫酸钠的敏感性增加，但对其他抗生素和去污剂的敏感性没有增加。已经确定了这些突变体的核苷酸序列。在所有情况下，成熟OmpC蛋白的第74位残基（精氨酸）受到影响。结果表明，OmpC蛋白的这一区域参与孔道结构域，并且这些改变导致孔径增大。
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