对Streptococcus pyogenes酶SpyCEP的结构活性研究显示,SpyCEP的C终端中对CXCL8具有很高的亲和力
Max Pearson1,2, Carl Haslam3, Andrew Fosberry3
1Department of Infectious Disease, Imperial College London, London, W12 0NN, UK.
Scientific reports
|November 4, 2023
概括
菌 pyogenes 细胞包膜蛋白酶 (SpyCEP) 对于疾病至关重要. 它的C端有助于基质结合,但N端对于充分的催化活性至关重要,揭示了关键的酶功能.
科学领域:
- 微生物学 微生物学
- 酶学 是一种酶学.
- 保护酶的功能 保护酶的功能
背景情况:
- 菌 pyogenes 细胞包膜蛋白酶 (SpyCEP) 对于病变发生至关重要.
- 除了ELR+CXC化学因子之外,SpyCEP的酶功能知识有限.
研究的目的:
- 调查SpyCEP酶功能所必需的蛋白质域和催化残留物.
- 使用一种新的测定方法,描述SpyCEP的酶动力学.
主要方法:
- 利用各种SpyCEP构造来分析蛋白质域和催化残留物.
- 开发并应用了一种高通量质谱测试方法,用于测量CXCL8裂纹.
- 确定了酶动力学,包括迈凯利斯-门顿常数 (KM) 和周转率.
主要成果:
- 在SpyCEP中,KM的低值为82nM,其转换率为1.65分子/秒.
- 一个N端截断的SpyCEP构造 (催化二H279/S617) 分裂了CXCL8的KM为55nM.
- 这种截断的结构显示活动减少了2200倍,表明N端在完全催化中的作用.
结论:
- 在SpyCEP的C端对于高亲和度基质的识别和结合至关重要.
- 为了实现完全的催化活性,SpyCEP的N端是必需的.
- 这些发现增强了对SpyCEP在链球菌病变发生过程中的作用的理解.
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