N-乙酰-D-葡萄糖胺的3-脱氧和6-脱氧衍生物与鸡溶菌酶的相互作用。

Interactions on 3-deoxy and 6-deoxy derivatives of N-acetyl-D-glucosamine with hen lysozyme.

作者信息

Kuramitsu S, Yang Y, Ikeda K, Hamaguchi K

出版信息

J Biochem. 1976 Sep;80(3):417-23. doi: 10.1093/oxfordjournals.jbchem.a131294.

DOI:10.1093/oxfordjournals.jbchem.a131294

Abstract

The interactions of deoxy derivatives of GlcNAc, 6-deoxy-GlcNAc, and 3-deoxy-GlcNAc with hen egg-white lysozyme [EC 3.2.1.17] were studied at various pH's by measuring the changes in the circular dichroic (CD) band at 295 nm. It was shown that 6-deoxy-GlcNAc and 3-deoxy-GlcNAc bind at subsite C of lysozyme and compete with GlcNAc. The pH dependence of the binding constant of 6-deoxy-GlcNAc was the same as that of GlcNAc. On the other hand, the binding constants of 3-deoxy-GlcNAc were 3--10 times smaller than those of GlcNAc in the pH range from 3 to 9. X-ray crystallographic studies show that O(6) and O(3) of GlcNAc at subsite C are hydrogen-bonded to the indole NH's of Trp 62 and Trp 63, respectively, but the above results indicate that Trp 63, not Trp 62, is important for the interaction of GlcNAc with lysozyme.

摘要

通过测量295nm处圆二色性（CD）谱带的变化，研究了N-乙酰葡糖胺（GlcNAc）的脱氧衍生物、6-脱氧-GlcNAc和3-脱氧-GlcNAc在不同pH值下与鸡蛋清溶菌酶[EC 3.2.1.17]的相互作用。结果表明，6-脱氧-GlcNAc和3-脱氧-GlcNAc结合在溶菌酶的C亚位点，并与GlcNAc竞争。6-脱氧-GlcNAc结合常数的pH依赖性与GlcNAc相同。另一方面，在pH值为3至9的范围内，3-脱氧-GlcNAc的结合常数比GlcNAc小3至10倍。X射线晶体学研究表明，C亚位点的GlcNAc的O(6)和O(3)分别与色氨酸62和色氨酸63的吲哚NH形成氢键，但上述结果表明，对于GlcNAc与溶菌酶的相互作用而言，色氨酸63而非色氨酸62是重要的。