N‐tail translocation of mature β‐lactamase across the Escherichia coli cytoplasmic membrane

FEBS Letters

Mitsopoulos, Costas¹  Hashemzadeh-Bonehi, Lida¹  Broome-Smith, Jenny K¹ 

[1] Biochemistry Group, School of Biological Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK

关键词: β-Lactamase;    Protein translocation;    Membrane protein;    N-tail;    Protein folding;    Escherichia coli;    SP;    signal peptide;    MSS;    membrane-spanning segment;    BlaM-gC;    mature β-lactamase-glycophorin C;    SP-BlaM-gC;    pre-β-lactamase-glycophorin C;    MIC;    minimum inhibitory concentration;    CAT;    chloramphenicol acetyltransferase;    IPTG;    isopropyl-1-thio-β-d-thiogalactopyranoside;    SDS-PAGE;    sodium dodecyl sulphate-polyacrylamide gel electrophoresis;    PMSF;    phenylmethylsulphonyl fluoride;    ECL;    enhanced chemiluminescence;   

DOI  :  10.1016/S0014-5793(97)01413-0

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Mature β-lactamase was attached to the N-terminus of human glycophorin C, an N-out membrane protein lacking a cleavable signal peptide (an N-tail membrane protein). When synthesised in Escherichia coli more than 30% of the intact mature β-lactamase-glycophorin C molecules assembled N-out, C-in into the cytoplasmic membrane. The N-tail translocated β-lactamase folded into an enzymatically active form, but it was more susceptible to proteolysis than the equivalent portion of β-lactamase-glycophorin C synthesised with an N-terminal signal peptide. Its translocation was virtually abolished when the N-out domain of glycophorin C was truncated or when the basic residues C-terminally flanking the glycophorin C membrane-spanning segment were replaced with neutral ones.

【 授权许可】

Unknown