MEMBRANE BIOGENESIS IN ESCHERICHIA-COLI - EFFECTS OF A SECA MUTATION
MEMBRANE BIOGENESIS IN ESCHERICHIA-COLI - EFFECTS OF A SECA MUTATION
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DOI：
10.1016/0005-2736(89)90418-5
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发表时间：
1989-11-03
期刊：
影响因子：
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通讯作者：
TOMMASSEN, J
中科院分区：
文献类型：
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作者：
DECOCK, H;MEELDIJK, J;TOMMASSEN, J
在大肠杆菌K-12中，这些ecA基因中的温度敏感性突变已被证明会干扰蛋白质输出。在这里，我们表明，asecAmutation的影响是强烈的多效性膜生物合成。冷冻断裂实验以及冷冻切片的细胞显示的外观胞质膜诱导SecA表型。外膜对清洁剂的渗透屏障消失。外膜中的两个改变可能是造成这种效应的原因，即外膜蛋白的量减少，或脂多糖的核心寡糖的长度减少，这在噬菌体敏感性实验和SDS-聚丙烯酰胺凝胶电泳中观察到。磷脂分析thesecAmutant，生长在限制性条件下，显示了较低的含量的带负电荷的磷脂心磷脂和18：1脂肪酸相比，在相同条件下生长的亲本菌株。这些结果符合蛋白质输出和脂质代谢耦合的假设。
InEscherichia coliK-12, temperature-sensitive mutations in thesecAgene have been shown to interfere with protein export. Here we show that the effect of asecAmutation is strongly pleiotropic on membrane biogenesis. Freeze-fracture experiments as well as cryosections of the cells revealed the appearance of intracytoplasmic membranes upon induction of the SecA phenotype. The permeability barrier of the outer membrane to detergents was lost. Two alterations in the outer membrane may be responsible for this effect, namely the reduced amounts of outer membrane proteins, or the reduction of the length of the core oligosaccharide of the lipopolysaccharide, which was observed in phage-sensitivity experiments and by SDS-polyacrylamide gel electrophoresis. Phospholipid analysis of thesecAmutant, grown under restrictive conditions, revealed a lower content of the negatively charged phospholipid cardiolipin and of 18:1 fatty acid compared to those of the parental strain grown under identical conditions. These results are in line with the hypothesis that protein export and lipid metabolism are coupled.