Igura Mayumi, Maita Nobuo, Obita Takayuki, Kamishikiryo Jun, Maenaka Katsumi, Kohda Daisuke
Division of Structural Biology, Medical Institute of Bioregulation, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582, Japan.
Acta Crystallogr Sect F Struct Biol Cryst Commun. 2007 Sep 1;63(Pt 9):798-801. doi: 10.1107/S1744309107040134. Epub 2007 Aug 31.
Oligosaccharyltransferase catalyzes the transfer of preassembled oligosaccharides onto asparagine residues in nascent polypeptide chains. The STT3 subunit is thought to bear the catalytic site. The C-terminal domain of the STT3 protein of Pyrococcus furiosus was expressed in Escherichia coli cells. STT3 protein prepared from two different sources, the soluble fraction and the inclusion bodies, produced crystals that diffracted to 2.7 A. During crystallization screening, cocrystals of P. furiosus STT3 with an E. coli 50S ribosomal protein, L7/L12, were accidentally obtained. This cross-species interaction is not biologically relevant, but may be used to design a built-in polypeptide substrate for the STT3 crystals.
寡糖基转移酶催化预组装寡糖转移到新生多肽链中的天冬酰胺残基上。人们认为STTSST�亚基具有催化位点。嗜热栖热菌的STT3蛋白的C端结构域在大肠杆菌细胞中表达。从两种不同来源（可溶性部分和包涵体）制备的STT3蛋白产生了衍射至2.7埃的晶体。在结晶筛选过程中，意外获得了嗜热栖热菌STT3与大肠杆菌50S核糖体蛋白L7/L12的共晶体。这种跨物种相互作用在生物学上不相关，但可用于为STT3晶体设计一种内置的多肽底物。
