A bacterial mutant library as a tool to study the attack of a defensin peptide.
A bacterial mutant library as a tool to study the attack of a defensin peptide.
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DOI：
10.1002/cbic.201402354
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发表时间：
2014-12-15
期刊：
影响因子：
3.2
通讯作者：
Nolan, Elizabeth M.
中科院分区：
文献类型：
--
作者：
Moser, Simone;Chileveru, Haritha R.;Tomaras, Jill;Nolan, Elizabeth M.
人类防御素是一种小的、富含半胱氨酸的宿主防御素，有助于天然免疫。[1]人类防御素5(Hd5ox)是一种32个残基的α-防御素，在小肠中高度表达，对多种细菌和真菌具有抗菌活性。尽管HD50x和防御素家族的许多其他多肽在人类健康和疾病中具有重要作用，但其作用机制尚不完全清楚。防御素通常被概括为膜通透性多肽，但除了膜破坏之外的抗菌机制已经被识别。我们基于模式生物大肠杆菌K-12的突变文库建立了一个无偏见的遗传筛选，以确定调节HD5ox易感性的细菌途径。该筛选产生了31个基因，在敲除时赋予HD5ox超敏反应，其中包括负责膜生物合成和完整性的基因。这些基因被独立证实为对HD5ox介导的大肠杆菌的杀灭起重要作用。此外，无偏筛选揭示了HD5ox和脂多糖之间的相互作用。HD5ox是一种α防御素，具有三链β-折叠二级结构，由三个保守的氧化形式的分子内二硫键(CysI-CysVI，CysII-CysIV，CysIII-CysV)稳定(图1A，B)。[2]该肽由小肠潘氏细胞[3]产生，在细菌攻击时释放到肠腔内。[4]HD5ox对包括革兰氏阴性大肠杆菌和革兰氏阳性金黄色葡萄球菌在内的多种物种显示出惊人的抗菌活性。[5]这种广谱和看似非特异性的活性使许多防御素具有典型性。这些多肽通常被描述为通过膜通透性起作用。事实上，一些研究表明，当细菌与不同的防御素孵育时，膜通透性发生[6]，而HD5ox处理会导致大肠杆菌内膜的破坏。[7]然而，最近的研究表明，防御素的作用机制不应一概而论，膜破坏只是影响抗菌活性的一个因素。真菌防御素、人类防御素6、9和人β-防御素2[10]和3[11]防御素在氨基酸序列、总电荷和
Human defensins are small, cysteine-rich host-defense peptides that contribute to innate immunity.[1] Human Defensin 5 (HD5ox) is a 32-residue α-defensin that is highly expressed in the small intestine and exhibits antimicrobial activity against a variety of bacterial and fungal species. Despite its importance in human health and disease, the mechanisms of action of HD5oxand many other peptides of the defensin family are not completely understood. Defensins are often generalized as membrane-permeabilizing peptides, but antibacterial mechanisms other than membrane disruption have been identified. We established an unbiased genetic screen based on a mutant library of the model organism Escherichia coli K-12 to identify bacterial pathways that modulate HD5ox susceptibility. The screen yielded thirty-one genes that confer hypersensitivity to HD5ox when knockedout, and included genes responsible for membrane biosynthesis and integrity. These genes were independently confirmed as being important for HD5ox-mediated killing of E. coli. Moreover, the unbiased screen uncovered an interaction between HD5ox and lipopolysaccharide.HD5ox is an α-defensin and features a triple-stranded β-sheet secondary structure that is stabilized by three conserved intramolecular disulfide bridges (CysI—CysVI, CysII—CysIV, CysIII—CysV) in the oxidized form (Figure 1A, B).[2] The peptide is produced by small intestinal Paneth cells [3] and released into the lumen upon bacterial challenge.[4] HD5ox displays antimicrobial activity against an impressively broad spectrum of species that include Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus.[5] Such broad-spectrum and seemingly unspecific activity typifies many defensins, and these peptides are often described to act by membrane permeabilization. Indeed, several studies demonstrated that membrane permeabilization occurs upon incubation of bacteria with various defensins,[6] and HD5ox treatment results in E. coli inner membrane damage.[7] Nevertheless, recent investigations delineate that the mechanism of action of defensins should not be generalized and that membrane disruption is only one factor governing antibacterial activity. Alternative antimicrobial or host-defense mechanisms are now appreciated for fungal plectasin,[8] human defensin 6,[9] and human β-defensins 2 [10] and 3.[11] Defensins differ significantly in amino acid sequence, overall charge, and
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影响因子：
4.4
作者：
Lehrer, Robert I.;Jung, Grace;Lu, Wuyuan
通讯作者：
Lu, Wuyuan
影响因子：
4.8
作者：
Satchell, DP;Sheynis, T;Jelinek, R
通讯作者：
Jelinek, R
DOI：
10.1073/pnas.1319066110
发表时间：
2013-12-10
影响因子：
11.1
作者：
Kandaswamy, Kumaravel;Liew, Tze Horng;Kline, Kimberly A.
通讯作者：
Kline, Kimberly A.
大肠杆菌K-12的构造框架，单基因敲除突变体：Keio Collection。
影响因子：
9.9
作者：
通讯作者：
--
影响因子：
14.9
作者：
Keseler IM;Mackie A;Peralta-Gil M;Santos-Zavaleta A;Gama-Castro S;Bonavides-Martínez C;Fulcher C;Huerta AM;Kothari A;Krummenacker M;Latendresse M;Muñiz-Rascado L;Ong Q;Paley S;Schröder I;Shearer AG;Subhraveti P;Travers M;Weerasinghe D;Weiss V;Collado-Vides J;Gunsalus RP;Paulsen I;Karp PD
通讯作者：
Karp PD