利用空肠弯曲菌的细菌寡糖基转移酶PglB进行糖肽的化学酶法合成。
Chemoenzymatic synthesis of glycopeptides with PglB, a bacterial oligosaccharyl transferase from Campylobacter jejuni.
作者信息
Glover Kerney Jebrell, Weerapana Eranthie, Numao Shin, Imperiali Barbara
机构信息
Department of Chemistry and Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA.
出版信息
Chem Biol. 2005 Dec;12(12):1311-5. doi: 10.1016/j.chembiol.2005.10.004.
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-alpha1,3-bacillosamine-pyrophosphate-undecaprenyl) and a peptide acceptor substrate (KDFNVSKA), we can observe the oligosaccharyl transferase activity of PgIB in vitro. Furthermore, the preparation of additional undecaprenyl-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.
革兰氏阴性菌空肠弯曲菌具有由pgl基因簇编码的一般N-连接糖基化途径。该基因簇中的一种蛋白质PgIB，由于其与酵母寡糖基转移酶复合物的一个亚基Stt3p具有显著同源性，被认为是寡糖基转移酶。PgIB已被证明参与催化十一异戊烯基连接的七糖转移到蛋白质Asn-X-Ser/Thr基序的天冬酰胺侧链上。使用合成二糖聚糖供体（GaINAc-α1,3-杆菌胺-焦磷酸-十一异戊烯基）和肽受体底物（KDFNVSKA），我们可以在体外观察到PgIB的寡糖基转移酶活性。此外，制备更多的十一异戊烯基连接的聚糖变体揭示了PgIB转移多种糖类的能力。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。
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