Pasteurella multocida (Pm) is a multi-species pathogen that causes diseases in animals and humans. Sialyltransferase activity has been detected in multiple Pm strains and sialylation has been shown to be important for the pathogenesis of Pm. Three putative sialyltransferase genes have been identified in Pm genomic strain Pm70. We have reported previously that a Pm0188 gene homolog in Pm strain P-1059 (ATCC 15742) encodes a multifunctional sialyltransferase (PmST1). We demonstrate here that while PmST1 prefers to use oligosaccharides as acceptors, PmST2 encoded by the Pm0508 gene homolog in the same Pm strain is a novel glycolipid α2-3-sialyltransferase that prefers to use lactosyl lipids as acceptor substrates. PmST2 and PmST1 thus complement each other for an efficient synthesis of α2-3-linked sialosides with or without lipid portion. In addition, β1-4-linked galactosyl lipids are better PmST2 substrates than β1-3-linked galactosyl lipids. PmST2 has been used successfully in the preparative scale synthesis of sialyllactosyl sphingosine (lyso-GM3), which is an important glycolipid and an intermediate for synthesizing more complex glycolipids such as gangliosides.
多杀性巴氏杆菌(Pm)是一种多物种病原体,可导致动物和人类疾病。在多个 Pm 菌株中检测到了
硅氨基转移酶活性,并证明
硅氨基化对 Pm 的致病机理非常重要。在 Pm
基因组菌株 Pm70 中发现了三个假定的
硅氨酰基转移酶基因。我们以前曾报道过,Pm 菌株
P-1059 (A
TCC 15742)中的 Pm0188
基因同源物编码一种多功能ialyl
转化酶(Pm
ST1)。我们在此证明,Pm
ST1 喜欢使用
寡糖作为接受基,而同一 Pm 菌株中的 Pm0508
基因同源物编码的 Pm
ST2 则是一种新型
糖脂 α2-3-
氨酰基转移酶,它喜欢使用
乳糖基脂类作为接受基。因此,Pm
ST2 和 Pm
ST1 相互补充,可高效合成含有或不含脂质部分的 α2-3 连接的半
乳糖苷。此外,β1-4 链半
乳糖基脂类是比 β1-3 链半
乳糖基脂类更好的 Pm
ST2 底物。Pm
ST2 已被成功地用于制备合成半
乳糖基鞘
磷脂(lyso-GM3),鞘
磷脂是一种重要的
糖脂,也是合成
神经节苷脂等更复杂
糖脂的
中间体。