A peptidoglycan recognition protein from Sciaenops ocellatus is a zinc amidase and a bactericide with a substrate range limited to Gram-positive bacteria
A peptidoglycan recognition protein from Sciaenops ocellatus is a zinc amidase and a bactericide with a substrate range limited to Gram-positive bacteria
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来自 Sciaenops ocellatus 的肽聚糖识别蛋白是一种锌酰胺酶和杀菌剂，底物范围仅限于革兰氏阳性菌
DOI：
10.1016/j.fsi.2011.11.024
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发表时间：
2012-02-01
影响因子：
4.7
通讯作者：
Sun, Li
中科院分区：
文献类型：
--
作者：
Li, Mo-Fei;Zhang, Min;Sun, Li
肽聚糖识别蛋白(PGRPs)是一类识别细菌肽聚糖的天然免疫分子。PGRPs在无脊椎动物和包括鱼类在内的脊椎动物中高度保守。然而，硬骨鱼PGRP的生物学功能在很大程度上仍未被研究。在本研究中，我们从红鱼中鉴定了一个PGRP同源物SoPGLYRP-2，并对其活性和潜在功能进行了分析。SoPGLYRP-2的氨基酸序列由482个残基组成，与已知的鱼类PGRPs有46-94%的同源性。SoPGLYRP-2在C末端含有单一的锌酰胺酶结构域，具有形成催化位点的保守残基。定量RT-PCR分析检测到SoPGLYRP-2在多种组织中的表达，其中肝脏表达最高，脑表达最低。实验性细菌感染以时间依赖的方式上调SoPGLYRP-2在肾、脾和肝脏的表达。为了研究SoPGLYRP-2的生物学活性，从大肠杆菌中制备了代表完整SoPGLYRP-2(rSoPGLYRP-2)和酰胺酶结构域(rSoPGLYRP-AD)的重组蛋白。随后的分析表明，rSoPGLYRP-2和rSoPGLYRP-AD(I)具有相似的锌依赖的肽聚糖活性，能够识别和结合活的细菌细胞，(Ii)对革兰氏阳性菌具有杀菌作用，对革兰氏阴性菌有轻微的抑菌作用，(Iii)能够阻止细菌感染宿主细胞。这些结果表明，SoPGLYRP-2是一种锌依赖的酰胺酶，是一种优先针对革兰氏阳性菌的杀菌剂，可能在细菌感染过程中发挥宿主天然免疫防御作用。(C)2011爱思唯尔有限公司。保留所有权利。
Peptidoglycan recognition proteins (PGRPs) are a family of innate immune molecules that recognize bacterial peptidoglycan. PGRPs are highly conserved in invertebrates and vertebrates including fish. However, the biological function of teleost PGRP remains largely uninvestigated. In this study, we identified a PGRP homologue, SoPGLYRP-2, from red drum (Sciaenops ocellatus) and analyzed its activity and potential function. The deduced amino acid sequence of SoPGLYRP-2 is composed of 482 residues and shares 46-94% overall identities with known fish PGRPs. SoPGLYRP-2 contains at the C-terminus a single zinc amidase domain with conserved residues that form the catalytic site. Quantitative RT-PCR analysis detected SoPGLYRP-2 expression in multiple tissues, with the highest expression occurring in liver and the lowest expression occurring in brain. Experimental bacterial infection upregulated SoPGLYRP-2 expression in kidney, spleen, and liver in time-dependent manners. To examine the biological activity of SoPGLYRP-2, purified recombinant proteins representing the intact SoPGLYRP-2 (rSoPGLYRP-2) and the amidase domain (rSoPGLYRP-AD) were prepared from Escherichia coli. Subsequent analysis showed that rSoPGLYRP-2 and rSoPGLYRP-AD (i) exhibited comparable Zn2+-dependent peptidoglycanlytic activity and were able to recognize and bind to live bacterial cells, (ii) possessed bactericidal effect against Gram-positive bacteria and slight bacteriostatic effect against Gram-negative bacteria, (iii) were able to block bacterial infection into host cells. These results indicate that SoPGLYRP-2 is a zinc-dependent amidase and a bactericide that targets preferentially at Gram-positive bacteria, and that SoPGLYRP-2 is likely to play a role in host innate immune defense during bacterial infection. (C) 2011 Elsevier Ltd. All rights reserved.