Escherichia coli phage-shock protein A (PspA) binds to membrane phospholipids and repairs proton leakage of the damaged membranes
Article first published online: 28 AUG 2007
Volume 66, Issue 1, pages 100–109, October 2007
How to Cite
Kobayashi, R., Suzuki, T. and Yoshida, M. (2007), Escherichia coli phage-shock protein A (PspA) binds to membrane phospholipids and repairs proton leakage of the damaged membranes. Molecular Microbiology, 66: 100–109. doi: 10.1111/j.1365-2958.2007.05893.x
- Issue published online: 28 AUG 2007
- Article first published online: 28 AUG 2007
- Accepted 31 July, 2007.
Escherichia coli phage-shock protein A (PspA), a 25.3 kDa peripheral membrane protein, is induced under the membrane stress conditions and is assumed to help maintain membrane potential. Here, we report that purified PspA, existing as a large oligomer, is really able to suppress proton leakage of the membranes. This was demonstrated for membrane vesicles prepared from the PspA-lacking E. coli mutants, and for membrane vesicles damaged by ethanol and Triton X-100 prepared from the mutant and the wild-type cells. PspA also suppressed proton leakage of damaged liposomes made from E. coli total lipids. Furthermore, we found that PspA bound preferentially to liposomes containing phosphatidylserine and phosphatidylglycerol. All these effects were not observed for monomer PspA that was prepared by refolding of urea-denatured PspA. These results indicate that oligomers of PspA bind to membrane phospholipids and suppress proton leakage.