共 186 条
Structural biology of membrane-intrinsic β-barrel enzymes: Sentinels of the bacterial outer membrane
被引:95
作者:
Bishop, Russell E.
[1
]
机构:
[1] McMaster Univ, Hlth Sci Ctr 4H19, Dept Biochem & Biomed Sci, Hamilton, ON L8N 3Z5, Canada
来源:
BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES
|
2008年
/
1778卷
/
09期
关键词:
OMPLA;
OmpT;
PagP;
PagL;
LpxR;
LpxQ;
D O I:
10.1016/j.bbamem.2007.07.021
中图分类号:
Q5 [生物化学];
Q7 [分子生物学];
学科分类号:
071010 ;
081704 ;
摘要:
The outer membranes of Gram-negative bacteria are replete with integral membrane proteins that exhibit antiparallel beta-barrel structures, but very few of these proteins function as enzymes. In Escherichia coli, only three beta-barrel enzymes are known to exist in the outer membrane; these are the phospholipase OMPLA, the protease OmpT, and the phospholipid: :lipid A palmitoyltransferase PagP, all of which have been characterized at the structural level. Structural details have also emerged for the outer membrane beta-barrel enzyme PagL, a lipid A 3-O-deacylase from Pseudomonas aeruginosa. Lipid A can be further modified in the outer membrane by two beta-barrel enzymes of unknown structure; namely, the Salmonella enterica 3'-acyloxyacyl hydrolase LpxR, and the Rhizobium legumniosarum oxidase LpxQ, which employs O-2 to convert the proximal glucosamine unit of lipid A into 2-aminogluconate. Structural biology now indicates how beta-barrel enzymes can function as sentinels that remain dormant when the outer membrane permeability barrier is intact. Host immune defenses and antibiotics that perturb this barrier can directly trigger beta-barrel enzymes in the outer membrane. The ensuing adaptive responses occur instantaneously and rapidly outpace other signal transduction mechanisms that similarly function to restore the outer membrane permeability barrier. (C) 2007 Elsevier B.V. All rights reserved.
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页码:1881 / 1896
页数:16
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