Isolation and preliminary characterization of wild-type OmpC porin dimers from Escherichia coli K-12.
Isolation and preliminary characterization of wild-type OmpC porin dimers from Escherichia coli K-12.
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大肠杆菌 K-12 野生型 OmpC 孔蛋白二聚体的分离和初步表征。
DOI：
10.1021/bi00435a017
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发表时间：
1989
期刊：
影响因子：
2.9
通讯作者：
E. McGroarty
中科院分区：
文献类型：
--
作者：
W. Rocque;E. McGroarty
大肠杆菌K-12菌株PLB3255含有ompF基因突变，导致孔蛋白缺失15个氨基酸。突变（dex）似乎增加了OmpF通道的大小，使PLB3255细胞能够在缺乏功能性麦芽糖蛋白的情况下在麦芽糊精上生长。从含有野生型ompC基因的菌株PLB3255中分离得到的孔蛋白通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳分离得到，孔蛋白含有50-60%的三聚体聚集体和35-40%的50-kDa“二聚体”。将分离的孔蛋白加热到100℃，在含有8 M尿素的SDS凝胶上分离，三聚体和“二聚体”在36 kDa的单条带中被回收，其迁移率与野生型OmpC孔蛋白相对应。对分离物的温度稳定性分析表明，与三聚体的81℃相比，OmpC“二聚体”在66℃时稳定性较差，并且变性。为了分离这些聚集体，将未加热的孔蛋白悬浮在30% SDS中，应用于Sephadex G-200凝胶过滤柱，并用0.5%脱氧胆酸钠洗脱。两个峰含有分离的三聚体和“二聚体”。二聚体和三聚体的圆二色性光谱显示出相似的β -结构。将分离的二聚体和三聚体重组成人工膜。通过平面双层脂质膜的电导率和脂质体肿胀试验表明，两株分离株具有相似的通道形成活性。另外四个相同表型的OmpC缺失突变体也显示产生50 kda的OmpC孔蛋白“二聚体”。（摘要删节250字）
Escherichia coli K-12 strain PLB3255 contains a mutation in the ompF gene that results in a 15 amino acid deletion in the porin protein. The mutation (dex) appears to increase the OmpF channel size, allowing the PLB3255 cells to grow on maltodextrins in the absence of a functional maltoporin. Porin isolated from strain PLB3255, which contains a wild-type ompC gene, was separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and shown to contain 50-60% trimer aggregates and 35-40% of a 50-kDa "dimer". When the porin isolate was heated to 100 degrees C and separated on SDS gels containing 8 M urea, both the trimer and the "dimer" were recovered in a single band at 36 kDa that corresponded in mobility to wild-type OmpC porin. An analysis of the temperature stability of the isolate showed that the OmpC "dimer" was less stable and denatured at 66 degrees C compared to 81 degrees C for the trimer. To separate these aggregates, the unheated porin was suspended in 30% SDS, applied to a Sephadex G-200 gel filtration column, and eluted with 0.5% sodium deoxycholate. Two peaks were recovered containing separated trimers and "dimers". Circular dichroism spectra of isolated dimers and trimers indicated similar amounts of beta-structure. The isolated dimers and trimers were reconstituted into artificial membranes. Electrical conductance across planar bilayer lipid membranes and liposome swelling assays showed that the two isolates had similar channel-forming activity. Four other ompF deletion mutants of the same phenotype were also shown to produce 50-kDa OmpC porin "dimers".(ABSTRACT TRUNCATED AT 250 WORDS)
铜绿假单胞菌孔蛋白的纯化和性质。
DOI：
--
发表时间：
1983
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Yoshimura,F;Zalman,LS;Nikaido,H
通讯作者：
Nikaido,H
DOI：
--
发表时间：
1988
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Reid,J;Fung,H;Gehring,K;Klebba,PE;Nikaido,H
通讯作者：
Nikaido,H