Chemoenzymatic synthesis of glycopeptides with PgIB, a bacterial oligosaccharyl transferase from Campylobacter jejuni
Chemoenzymatic synthesis of glycopeptides with PgIB, a bacterial oligosaccharyl transferase from Campylobacter jejuni
复制标题
DOI：
10.1016/j.chembiol.2005.10.004
复制
发表时间：
2005-12-01
影响因子：
--
通讯作者：
Imperiali, B
中科院分区：
文献类型：
--
作者：
Glover, KJ;Weerapana, E;Imperiali, B
革兰氏阴性细菌空肠弯曲杆菌具有由pgl基因簇编码的一般N-连接糖基化途径。该簇中的蛋白质之一PgIB被认为是寡糖基转移酶，因为其与酵母寡糖基转移酶复合物的亚基Stt 3 p具有显著的同源性。PgIB已显示参与催化十一异戊二烯基连接的七糖转移到蛋白质的天冬酰胺侧链的Asn-X-Ser/Thr基序。使用合成的二糖聚糖供体（GaINAc-α 1，3-杆菌胺-焦磷酸-unclecaprenyl）和肽受体底物（KD FNVSKA），我们可以在体外观察PgIB的寡糖基转移酶活性。此外，额外的unclecaprenyl-连接的聚糖变体的制备揭示了PgIB转移多种底物的能力。随着PgIB体外活性的证明，现在可以解决围绕N-连接糖基化机制的基本问题。
The gram-negative bacterium Campylobacter jejuni has a general N-linked glycosylation pathway encoded by the pgl gene cluster. One of the proteins in this cluster, PgIB, is thought to be the oligosaccharyl transferase due to its significant homology to Stt3p, a subunit of the yeast oligosaccharyl transferase complex. PgIB has been shown to be involved in catalyzing the transfer of an undecaprenyl-linked heptasaccharide to the asparagine side chain of proteins at the Asn-X-Ser/Thr motif. Using a synthetic disaccharide glycan donor (GaINAc-alpha l,3-bacillosamine-pyrophosphate-unclecaprenyl) and a peptide acceptor substrate (KD FNVSKA), we can observe the oligosaccharyl transferase activity of PgIB in vitro. Furthermore, the preparation of additional unclecaprenyl-linked glycan variants reveals the ability of PgIB to transfer a wide variety of saccharides. With the demonstration of PgIB activity in vitro, fundamental questions surrounding the mechanism of N-linked glycosylation can now be addressed.