Mukherjee Raju, Chatterji Dipankar
Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India.
Biochem Biophys Res Commun. 2005 Dec 16;338(2):964-72. doi: 10.1016/j.bbrc.2005.10.038. Epub 2005 Oct 21.
The alternate sigma factor, sigB, is known to play a crucial role in maintaining the stationary phase in mycobacteria. In this communication, we have studied the proteomics of Mycobacterium smegmatis mc(2)155 and its two derivatives, one of which has a disrupted sigB gene and the other, PMVSigB, which contains a multicopy plasmid containing sigB. We have identified by two-dimensional gel analyses, several proteins that are over-expressed in PMVSigB compared to mc(2)155. These proteins are either stress proteins or participate actively in different metabolic pathways of the organisms. On the other hand, when sigB deleted mycobacteria were grown until the stationary phase and its two-dimensional protein profile was compared to that of mc(2)155, few DNA binding proteins were found to be up-regulated. We have shown recently that upon over-expressing sigB, the cell surface glycopeptidolipids of M. smegmatis are hyperglycosylated, a situation similar to what was observed for nutritionally starved bacteria. Gene expression profile through quantitative PCR presented here identified a Rhamnosyltransferase responsible for this hyperglycosylation.
已知替代σ因子sigB在分枝杆菌维持稳定期方面发挥关键作用。在本交流文章中，我们研究了耻垢分枝杆菌mc(2)155及其两个衍生物的蛋白质组学，其中一个衍生物的sigB基因被破坏，另一个是PMVSigB，它含有一个携带sigB的多拷贝质粒。通过二维凝胶分析，我们鉴定出了几种与mc(2)155相比在PMVSigB中过表达的蛋白质。这些蛋白质要么是应激蛋白，要么积极参与生物体的不同代谢途径。另一方面，当缺失sigB的分枝杆菌生长至稳定期并将其二维蛋白质谱与mc(2)155的进行比较时，发现少数DNA结合蛋白上调。我们最近表明，过表达sigB后，耻垢分枝杆菌的细胞表面糖肽脂会发生高糖基化，这种情况与营养饥饿细菌中观察到的类似。此处通过定量PCR呈现的基因表达谱鉴定出了一种负责这种高糖基化的鼠李糖基转移酶。
