Ariöz Candan, Götzke Hansjörg, Lindholm Ljubica, Eriksson Jonny, Edwards Katarina, Daley Daniel O, Barth Andreas, Wieslander Ake
The Arrhenius Laboratories for Natural Sciences, Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden.
The Arrhenius Laboratories for Natural Sciences, Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden.
Biochim Biophys Acta. 2014 Jul;1838(7):1862-70. doi: 10.1016/j.bbamem.2014.04.001. Epub 2014 Apr 12.
The membrane protein monoglucosyldiacylglycerol synthase (MGS) from Acholeplasma laidlawii is responsible for the creation of intracellular membranes when overexpressed in Escherichia coli (E. coli). The present study investigates time dependent changes in composition and properties of E. coli membranes during 22h of MGS induction. The lipid/protein ratio increased by 38% in MGS-expressing cells compared to control cells. Time-dependent screening of lipids during this period indicated differences in fatty acid modeling. (1) Unsaturation levels remained constant for MGS cells (~62%) but significantly decreased in control cells (from 61% to 36%). (2) Cyclopropanated fatty acid content was lower in MGS producing cells while control cells had an increased cyclopropanation activity. Among all lipids, phosphatidylethanolamine (PE) was detected to be the most affected species in terms of cyclopropanation. Higher levels of unsaturation, lowered cyclopropanation levels and decreased transcription of the gene for cyclopropane fatty acid synthase (CFA) all indicate the tendency of the MGS protein to force E. coli membranes to alter its usual fatty acid composition.
来自莱氏无胆甾原体的膜蛋白单葡萄糖基二酰甘油合酶（MGS）在大肠杆菌中过表达时负责细胞内膜的形成。本研究调查了在MGS诱导22小时期间大肠杆菌膜的组成和性质随时间的变化。与对照细胞相比，表达MGS的细胞中脂质/蛋白质比率增加了38%。在此期间对脂质进行的时间依赖性筛选表明脂肪酸模式存在差异。（1）MGS细胞的不饱和度保持恒定（约62%），而对照细胞的不饱和度显著降低（从61%降至36%）。（2）产生MGS的细胞中环丙烷化脂肪酸含量较低，而对照细胞的环丙烷化活性增加。在所有脂质中，就环丙烷化而言，磷脂酰乙醇胺（PE）被检测为受影响最大的种类。更高的不饱和度水平、更低的环丙烷化水平以及环丙烷脂肪酸合酶（CFA）基因转录的减少都表明MGS蛋白促使大肠杆菌膜改变其通常脂肪酸组成的趋势。
