Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway.
FEBS Lett. 2011 Jul 21;585(14):2339-44. doi: 10.1016/j.febslet.2011.06.002. Epub 2011 Jun 12.
The contributions of the -3 subsite and a putative +3 subsite to substrate positioning in ChiA from Serratia marcescens have been investigated by comparing how ChiA and its -3 subsite mutant W167A interact with soluble substrates. The data show that Trp - GlcNAc stacking in the -3 subsite rigidifies the protein backbone supporting the formation of the intermolecular interaction network that is necessary for the recognition and positioning of the N-acetyl groups before the -1 subsite. The +3 subsite exhibits considerable substrate affinity that may promote endo-activity in ChiA and/or assist in expelling dimeric products from the +1 and +2 subsites during processive hydrolysis.
已经通过比较 ChiA 及其 -3 亚基突变体 W167A 与可溶性底物的相互作用，研究了来自粘质沙雷氏菌的 ChiA 中 -3 亚基和假定的 +3 亚基对底物定位的贡献。数据表明，-3 亚基中色氨酸 - GlcNAc 堆积使蛋白质骨架变硬，支持形成分子间相互作用网络，这对于识别和定位 -1 亚基之前的 N-乙酰基基团是必要的。+3 亚基表现出相当大的底物亲和力，这可能促进 ChiA 的内切活性，和/或在连续水解过程中协助从 +1 和 +2 亚基中排出二聚产物。
