Salmonella enterica FraB deglycase 的晶体结构揭示了在活性部位具有显著的结构可塑性的一种构型异构体
Katerina Zakharova1, Jamison D Law2,3, Yuan Gao3,4,5
1Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, Ohio, USA.
Protein science : a publication of the Protein Society
|August 18, 2025
概括
沙门氏菌FraB酶经历了显著的构造变化,揭示了一个灵活的活性部位,对果糖-黄素代谢至关重要. 这些结构洞察力阐明了酶的催化机制和基质结合动态.
科学领域:
- 结构生物学 结构生物学
- 酶学 是一种酶学.
- 微生物的新陈代谢
背景情况:
- 在Salmonella enterica中的fra locus编码了果糖-氨酸代谢的酶.
- FraB 是一种对6--果糖-酸盐裂变至关重要的降糖剂.
- 同性学模型表明,FraB形成一个同分体,在二分体接口上有活性位点.
研究的目的:
- 通过晶体结构阐明FraB酶活性的结构基础.
- 调查关键催化残留物 (E214,H230) 和C端残留物在FraB函数中的作用.
- 了解FraB二元体在催化过程中的结构动力学.
主要方法:
- 确定野生类型类似FraB及其变体的六个晶体结构.
- 结构分析包括N端His6标记,活性位子突变 (E214A,P232A) 和C端删除变体.
- 结构形状的比较,以了解催化残留物定位和活性部位可塑性.
主要成果:
- 野生类型的FraB结构显示了催化残留物E214和H230大约相隔22 Å.
- 突变和截断的FraB变体表现出形状变化,使E214和H230*更接近 (~7 Å).
- H230轴承环和C端尾部表现出显著的形状灵活性,影响了基板接入.
结论:
- FraB 作为一种构型异构体,具有相同的子单元,在催化过程中采用不同的结构.
- 酶可塑性,涉及活性位点的相关打开和关闭,对于基质结合和释放至关重要.
- 结构洞察力为FraB在果糖-菜代谢中的作用提供了机械的理解.
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