GNA33 of Neisseria meningitidis is a lipoprotein required for cell separation, membrane architecture, and virulence
GNA33 of Neisseria meningitidis is a lipoprotein required for cell separation, membrane architecture, and virulence
复制标题
DOI：
10.1128/iai.72.4.1914-1919.2004
复制
发表时间：
2004-04-01
影响因子：
3.1
通讯作者：
Pizza, M
中科院分区：
文献类型：
--
作者：
Adu-Bobie, J;Lupetti, P;Pizza, M
GNA33是一种膜结合型脂蛋白，具有毛霉素水解酶活性，存在于所有奈瑟氏菌中，并在不同脑膜炎球菌分离株中保存良好。该蛋白与来自大肠杆菌的裂解转乙醇酶(MltA)有33%的同源性，并已被证明参与不溶性毛瑞林球囊和未被取代的糖链的降解。为了研究该基因的功能及其在致病和毒力中的作用，我们产生了脑膜炎奈瑟氏菌B群菌株的敲除突变株。该突变体在体外表现出生长迟缓。透射电子显微镜显示，突变体以簇状生长，由连续的外膜连接，这表明子代细胞分离失败。此外，对培养上清液进行十二烷基硫酸钠-聚丙烯酰胺凝胶电泳分析表明，该突变株在培养上清液中释放了几种蛋白质。经基质辅助激光解吸电离飞行时间质谱仪鉴定的5种最丰富的蛋白质属于外膜蛋白家族。最后，突变体表现出一种减弱的表型，因为它不能在幼鼠模型中引起菌血症。我们认为GNA33是一种高度保守的脂蛋白，在肽聚糖代谢、细胞分离、膜结构和毒力等方面发挥着重要作用。
GNA33 is a membrane-bound lipoprotein with murein hydrolase activity that is present in all Neisseria species and well conserved in different meningococcal isolates. The protein shows 33% identity to a lytic transglycolase (MltA) from Escherichia coli and has been shown to be involved in the degradation of both insoluble murein sacculi and unsubstituted glycan strands. To study the function of the gene and its role in pathogenesis and virulence, a knockout mutant of a Neisseria meningitidis serogroup B strain was generated. The mutant exhibited retarded growth in vitro. Transmission electron microscopy revealed that the mutant grows in clusters which are connected by a continuous outer membrane, suggesting a failure in the separation of daughter cells. Moreover, sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of culture supernatant revealed that the mutant releases several proteins in the medium. The five most abundant proteins, identified by matrix-assisted laser desorption ionization-time-of-flight mass spectrometry analysis, belong to the outer membrane protein family. Finally, the mutant showed an attenuated phenotype, since it was not able to cause bacteremia in the infant rat model. We conclude that GNA33 is a highly conserved lipoprotein which plays an important role in peptidoglycan metabolism, cell separation, membrane architecture, and virulence.