Crystal Structure of Ser-22/Ile-25 Form Crambin Confirms Solvent, Side Chain Substate Correlations*-猫眼课题宝

Ser-22/Ile-25 形式 Crambin 的晶体结构证实了溶剂、侧链底物相关性*

DOI：

发表时间：

1997

期刊：

Journal of Biological Chemistry

影响因子：

4.8

通讯作者：

中科院分区：

生物学2区

文献类型：

作者：

A. Yamano;N. Heo;M. Teeter

人们不同意，无序的蛋白质侧链的相关位置（亚态相关性）可以从衍射数据推导出来。纯的Ser-22/Ile-25（SI形式）crambin晶体结构证实了针对天然的、混合序列形式的crambin晶体推导的相关性。将混合形式物理分离成纯SI形式和Pro-22/Leu-25（PL形式）crambin，并测定PL形式晶体结构（Yamano，A.，和Teeter，M. M.（1994）J.Biol.Chem.269，13956-13965）支持提出的（Teeter，M. M.，Roe，S. M.，和Heo，N. H.等人（1993）J. Mol. Biol. 230，292-311）相关模型。混合形式的crambin晶体的电子密度示出了异质残基22和附近的Tyr-29（22 = 4，两个侧链中的每一个的两个构象）的四种可能的侧链构象对。由于短的货车德瓦耳斯接触，可以消除一个组合。然而，只有两种替代物被假定以混合形式存在：Pro-22/Tyr-29 A和Ser-22/Tyr-29 B。在PL形式的晶体中，发现Pro-22和Tyr-29 A直接货车德瓦耳斯接触（Yamano，A.，和Teeter，M. M.（1994）J.Biol.Chem.269，13956-13965）。SI形式的结构与混合形式的电子密度的比较证实，侧链的第四组合不发生，侧链的相关性介导的水网络。

It is not agreed that correlated positions of disordered protein side chains (substate correlations) can be deduced from diffraction data. The pure Ser-22/Ile-25 (SI form) crambin crystal structure confirms correlations deduced for the natural, mixed sequence form of crambin crystals. Physical separation of the mixed form into pure SI form and Pro-22/Leu-25 (PL form) crambin and the PL form crystal structure determination (Yamano, A., and Teeter, M. M. (1994) J. Biol. Chem. 269, 13956-13965) support the proposed (Teeter, M. M., Roe, S. M., and Heo, N. H. (1993) J. Mol. Biol. 230, 292-311) correlation model. Electron density of mixed form crambin crystals shows four possible pairs of side chain conformations for heterogeneous residue 22 and nearby Tyr-29 (22 = 4, two conformations for each of two side chains). One combination can be eliminated because of short van der Waals' contacts. However, only two alternates have been postulated to exist in mixed form crambin: Pro-22/Tyr-29A and Ser-22/Tyr-29B. In crystals of the PL form, Pro-22 and Tyr-29A are found to be in direct van der Waals' contact (Yamano, A., and Teeter, M. M. (1994) J. Biol. Chem. 269, 13956-13965). Comparison of the SI form structure with the mixed form electron density confirms that the fourth combination of side chains does not occur and that side chain correlations are mediated by water networks.