Identification of critical residues of O-antigen-modifying O-acetyltransferase B (OacB) of Shigella flexneri.
Identification of critical residues of O-antigen-modifying O-acetyltransferase B (OacB) of Shigella flexneri.
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DOI：
10.1186/s12860-022-00415-8
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发表时间：
2022-03-24
影响因子：
2.8
通讯作者：
Verma NK
中科院分区：
文献类型：
--
作者：
Rajput MI;Verma NK
志贺氏菌病是一种急性胃肠道疾病，主要由福氏志贺氏菌引起。摄入后，弗氏链球菌会启动针对病原体脂多糖的 O 抗原的血清型特异性免疫反应。 O-抗原亚基通过添加化学部分进行修饰，从而产生福氏链球菌的新血清型。福氏链球菌有 19 种不同的血清型已被识别。最近鉴定的 O-抗原修饰酶 O-乙酰转移酶 B (OacB)，它在血清型 1a、1b、2a、5a、7a、Y 和 6 的鼠李糖 III 的 3 或 4 位（3/4-O-乙酰化）和血清型 2a 的 N-乙酰葡萄糖胺（6-O-乙酰化）的 6 位添加乙酰残基， 3a、O-抗原亚基的Y和Yv。参与 O 抗原修饰的其他蛋白质（例如福氏链霉的葡萄糖基转移酶 (Gtrs) 和乙酰转移酶 (Oac)）中的关键残基已被鉴定，而 OacB 功能中重要氨基酸的鉴定尚未确定。疏水性分析表明，OacB 是一种跨膜蛋白，具有 11 个跨膜片段、12 个环以及周质 N 端和细胞质 C 端。生物信息学分析表明OacB含有乙酰转移酶3结构域和几个保守残基。使用定点诱变，将选定的氨基酸突变为丙氨酸，以阐明它们在 OacB 作用机制中的作用。研究发现 7 个氨基酸 R47、H58、F98、W71、R116、R119 和 S146 对 OacB 功能至关重要。由于缺乏血清型转换酶 O-乙酰转移酶 B (OacB) 的三维结构，因此排除了重要残基在作用机制中的明确作用。因此，在本研究中，利用定点诱变，鉴定了对 OacB 功能至关重要的七个残基。在抗血清存在下，表达突变型OacB的细胞不发生凝集，这表明了相应残基的功能作用。因此，这项研究提供了有关 OacB 中关键残基的重要信息，这些残基可能参与形成福氏链霉 O 抗原修饰酶的催化位点。在线版本包含可在 10.1186/s12860-022-00415-8 获取的补充材料。
Shigellosis is an acute gastrointestinal disease caused primarily by the bacterium Shigella flexneri. Upon ingestion, S. flexneri initiates a serotype-specific immune response that targets the O-antigen of the pathogen’s lipopolysaccharide. O-antigen subunits are modified by the addition of chemical moieties, which give rise to new serotypes of S. flexneri. Nineteen different serotypes of S. flexneri have been recognized. A recently identified O-antigen-modifying enzyme, O-acetyltransferase B (OacB), which adds an acetyl residue at either position 3 or 4 of RhamnoseIII (3/4-O-acetylation) in serotypes 1a, 1b, 2a, 5a, 7a, Y, and 6 and position 6 of N- acetylglucosamine (6-O-acetylation) in serotypes 2a, 3a, Y and Yv of the O-antigen subunits. Critical residues in other proteins involved in O-antigen modifications such as glucosyltransferases (Gtrs) and acetyltransferase (Oac) of S. flexneri have been identified, whereas identification of important amino acids in OacB function is yet to be determined. Hydrophobicity analysis showed that OacB is a transmembrane protein with 11 transmembrane segments, 12 loops, and periplasmic N- and cytoplasmic C- termini. Bioinformatics analyses revealed that OacB contains acetyltransferase-3 domain and several conserved residues. Using site-directed mutagenesis, selected amino acids were mutated to alanine to elucidate their role in the mechanism of action of OacB. Seven amino acids R47, H58, F98, W71, R116, R119, and S146 were found critical for the OacB function. In the absence of a three-dimensional structure of the serotype converting enzyme, O-acetyltransferase B (OacB), a clear role of important residues in the mechanism of action is precluded. Therefore, in this study, using site-directed mutagenesis, seven residues critical to the function of OacB were identified. The lack of agglutination of cell expressing mutant OacB in the presence of the antiserum indicated the functional role of the corresponding residues. Hence, this study provides significant information about key residues in OacB which might be involved in forming the catalytic sites of this O-antigen modifying enzyme of S. flexneri. The online version contains supplementary material available at 10.1186/s12860-022-00415-8.
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影响因子：
14.9
作者：
Tsirigos KD;Peters C;Shu N;Käll L;Elofsson A
通讯作者：
Elofsson A
影响因子：
4.9
作者：
Shmara, A;Weinsetel, N;Tolmasky, ME
通讯作者：
Tolmasky, ME
介导福氏志贺菌 O 抗原中鼠李糖 III 3-和 4-O-乙酰化的 O-酰基转移酶基因 (oacB) 的鉴定
影响因子：
3.2
作者：
Wang, Jianping;Knirel, Yuriy A.;Sun, Qiangzheng
通讯作者：
Sun, Qiangzheng
影响因子：
4.1
作者：
Goodfellow, GH;Dupret, JM;Grant, DM
通讯作者：
Grant, DM
影响因子：
--
作者：
Perepelov, Andrei V.;Shekht, Maria E.;Knirel, Yuriy A.
通讯作者：
Knirel, Yuriy A.