乳球菌乳糖化酶的全性行为和基质特异性的结构基础
Shangyi Xu1, Pawel Grochulski2, Takuji Tanaka1
1Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, SK, Canada.
Biochimica et biophysica acta. Proteins and proteomics
|January 15, 2024
概括
乳球球菌乳酸益化酶 (Llprol) 由于其二次结构而表现出全性行为. 突变通过影响单体间相互作用和活性部位的可访问性来改变这种行为,揭示了对酶调节的洞察力.
科学领域:
- 酶学 是一种酶学.
- 结构生物学 结构生物学
- 生物化学 生物化学
背景情况:
- 普罗利达酶 (EC 3.4.13.9) 催化Xaa-Pro二化水解.
- 野生类型的乳球菌乳糖酶 (Llprol) 显示出独特的全性行为和基质抑制.
- 之前的研究确定了Llprol的动力特性和晶体结构.
研究的目的:
- 为了阐明Llprol全性行为的结构基础.
- 研究特定突变 (D36S,H38S,R293S) 对Llprol动力学和结构的功能影响.
- 了解单体相互作用如何影响酶活性和基质结合.
主要方法:
- 通过X射线晶体学,解决了三种Llprol突变体 (D36S,H38S,R293S) 的结构.
- 对野生类型和突变Llprol.的动态数据 (v-S图) 的分析.
- 对Llprol变体进行比较结构分析,以确定单体定位和接口特征的差异.
主要成果:
- 突变D36S和R293S失去了全性行为,而H38S保留了与野生类型Llprol相似的全性.
- Llprol的活性位点位于二聚体接口,涉及两种单体的残留物.
- 结构比较显示了Llprol变体之间的单体相对位置,原子间距离和接口区域的变化.
- 在低基质度下不对称的二元激活与野生类型和H38S Llprol.的全性行为有关.
结论:
- Llprol的全性行为与其二维结构和其在界面上的活性位点的结构灵活性密切相关.
- 特定的突变可以破坏精确的单体间调节所需的精确的单体间安排.
- 酶适应构造状态的能力会影响基质亲和力和催化活性,为酶化提供了一个模型.
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