Glycosylation of multiple proteins via O-linkage is well documented in bacterial species of Neisseria of import to human disease. Recent studies of protein glycosylation (pgl) gene distribution established that related protein glycosylation systems occur throughout the genus including nonpathogenic species. However, there are inconsistencies between pgl gene status and observed glycan structures. One of these relates to the widespread distribution of pglG, encoding a glycosyltransferase that in Neisseria elongata subsp. glycolytica is responsible for the addition of di-N-acetyl glucuronic acid at the third position of a tetrasaccharide. Despite pglG residing in strains of N. gonorrhoeae, N. meningitidis and N. lactamica, no glycan structures have been correlated with its presence in these backgrounds. Moreover, PglG function in N. elongata subsp. glycolytica minimally requires UDP-glucuronic acid (GlcNAcA), and yet N. gonorrhoeae, N. meningitidis and N. lactamica lack pglJ, the gene whose product is essential for UDP-GlcNAcA synthesis. We examined the functionality of pglG alleles from species spanning the Neisseria genus by genetic complementation in N. elongata subsp. glycolytica. The results indicate that select pglG alleles from N. meningitidis and N. lactamica are associated with incorporation of an N-acetyl-hexosamine at the third position and reveal the potential for an expanded glycan repertoire in those species. Similar experiments using pglG from N. gonorrhoeae failed to find any evidence of function suggesting that those alleles are missense pseudogenes. Taken together, the results are emblematic of how allelic polymorphisms can shape bacterial glycosyltransferase function and demonstrate that such alterations may be constrained to distinct phylogenetic lineages.

中文翻译：

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奈瑟氏球菌O-连接蛋白糖基化系统中糖基转移酶基因的等位基因多态性形成聚糖库

多种蛋白质通过O键的糖基化在对人类疾病有重要影响的奈瑟氏球菌细菌种类中得到充分证明。最近对蛋白质糖基化 ( pgl ) 基因分布的研究表明，相关的蛋白质糖基化系统存在于整个属中，包括非致病性物种。然而， pgl基因状态和观察到的聚糖结构之间存在不一致。其中之一与pglG的广泛分布有关，它编码长奈瑟球菌亚种中的糖基转移酶。糖酵解负责添加 di- N-乙酰葡萄糖醛酸在四糖的第三位。尽管pglG存在于淋病奈瑟菌、脑膜炎奈瑟菌和乳酸奈瑟菌的菌株中，但没有聚糖结构与其在这些背景中的存在相关联。此外，PglG 在N. elongata subsp. 中起作用。糖酵解菌对 UDP-葡萄糖醛酸 (GlcNAcA) 的需求最低，而淋病奈瑟菌、脑膜炎奈瑟菌和乳酸奈瑟菌缺乏pglJ，该基因的产物对 UDP-GlcNAcA 合成至关重要。我们检查了跨越物种的pglG等位基因的功能N. elongata亚种中通过遗传互补的奈瑟球菌属。糖酵解菌。结果表明，来自脑膜炎奈瑟菌和乳酸奈瑟菌的选择pglG等位基因与在第三个位置掺入N-乙酰基-己糖胺有关，并揭示了这些物种中扩展聚糖库的潜力。使用来自淋病奈瑟菌的pglG进行类似的实验未能找到任何功能证据表明这些等位基因是错义假基因。总之，这些结果象征着等位基因多态性如何塑造细菌糖基转移酶功能，并证明这种改变可能仅限于不同的系统发育谱系。