期刊
JOURNAL OF BACTERIOLOGY
卷 187, 期 7, 页码 2448-2457出版社
AMER SOC MICROBIOLOGY
DOI: 10.1128/JB.187.7.2448-2457.2005
关键词
-
类别
资金
- NIAID NIH HHS [R01 AI030479, AI-30479] Funding Source: Medline
Salmonella enterica serovar Typhimurium remodels the lipid A component of lipopolysaccharide, a major component of the outer membrane, to survive within animals. The activation of the sensor kinase PhoQ in host environments increases the synthesis of enzymes that deacylate, palmitoylate, hydroxylate, and attach aminoarabinose to lipid A, also known as endotoxin. These modifications promote bacterial resistance to antimicrobial peptides and reduce the host recognition of lipid A by toll-like receptor 4. The Salmonella lipid A 3-O-deacylase, PagL, is an outer membrane protein whose expression is regulated by PhoQ. In S. enterica serovar Typhimurium strains that had the ability to add aminoarabinose to lipid A, 3-O-deacylated lipid A species were not detected, despite the PhoQ induction of PagL protein expression. In contrast, strains defective for the aminoarabinose modification of lipid A demonstrated in vivo PagL activity, indicating that this membrane modification inhibited PagL's enzymatic activity. Since not all lipid A molecules are modified with aminoarabinose upon PhoQ activation, these results cannot be ascribed to the substrate specificity of PagL. PagL-dependent deacylation was detected in sonically disrupted membranes and membranes treated with the nonionic detergent n-octyl-beta-D-glucopyranoside, suggesting that perturbation of the intact outer membrane releases PagL from posttranslational inhibition by aminoarabinose-containing membranes. Taken together, these results suggest that PagL enzymatic deacylation is posttranslationally inhibited by membrane environments, which either sequester PagL from its substrate or alter its conformation.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据