Altered voltage sensitivity of mutant OmpC porin channels

FEBS Letters

Mobasheri, H.¹  Spiro, S.¹  Bishop, N.D.¹  Lea, E.J.A.¹ 

[1] School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK

关键词: Porin;    Outer membrane protein;    Oligonucleotide-directed mutagenesis;    Thermal stability;    Escherischia coli;   

DOI  :  10.1016/0014-5793(95)01535-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Single OmpC porin channels have been reconstituted in planar bilayer membranes. Wild-type OmpC forms trimers which are largely insensitive to voltages below 250 mV. A single-point mutation of the ompC gene has been prepared resulting in replacement of Trp56 by Cys in the eyelet region of the channel wall in a highly conserved segment of the polypeptide. The monomeric channels of which the trimer is composed have smaller conductivity in 1 M NaCl (400 ± 20 pS, mean and S.E.M., n = 30) and increased voltage sensitivity by comparison with the wild-type under similar conditions, whereas other (Dex) mutants form larger channels and display different behaviour. Further, by treatment in SDS solutions at different temperatures, the W56C mutant has been shown to be less stable than either the wild-type or the Dex mutants.

【 授权许可】

Unknown