来自大肠杆菌的S-腺苷甲硫氨酸合成酶。晶体化及初步X射线衍射研究。

S-adenosylmethionine synthetase from Escherichia coli. Crystallization and preliminary X-ray diffraction studies.

作者信息

Gilliland G L, Markham G D, Davies D R

出版信息

J Biol Chem. 1983 Jun 10;258(11):6963-4.

Abstract

S-Adenosylmethionine synthetase from Escherichia coli can be crystallized by the method of vapor diffusion using ammonium sulfate as the precipitant. Two of several crystal forms of the tetrameric (Mr = 180,000) enzyme have been examined by x-ray diffraction methods. One form, a hexagonal bipyramid, develops when Mg2+ and PPi are added to the protein solution. The space group is P62(22) or P64(22) with a = b = 128.8 A, c = 140.0 A, and one subunit in the asymmetric unit. The other, a regular octrahedron, forms with the addition of 5% (v/v) 2-methyl-2,4-pentanediol. It is of space group P41(2)1(2) or P4(3)2(1)2, with a = b = 121.8 A, c = 172.6 A, and two subunits in the asymmetric unit.

摘要

来自大肠杆菌的S-腺苷甲硫氨酸合成酶可以通过以硫酸铵作为沉淀剂的气相扩散法进行结晶。已通过X射线衍射方法研究了四聚体（Mr = 180,000）酶的几种晶体形式中的两种。一种形式是六方双锥体，当向蛋白质溶液中加入Mg2+和PPi时形成。空间群为P62(22)或P64(22)，a = b = 128.8 Å，c = 140.0 Å，不对称单元中有一个亚基。另一种是规则八面体，在加入5%（v/v）2-甲基-2,4-戊二醇时形成。它的空间群为P41(2)1(2)或P4(3)2(1)2，a = b = 121.8 Å，c = 172.6 Å，不对称单元中有两个亚基。