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作为酶的LexA和lambda Cl抑制剂:在分子间反应中的特定裂变

B Kim¹, J W Little

¹Department of Biochemistry, University of Arizona, Tucson 85721.

|June 18, 1993

概括

莱克斯A抑制蛋白可以分裂,其C端片段作为酶. 这种分子间裂变机制也在lambda Cl抑制剂中观察到,为DNA修复和prophage诱导提供了洞察力.

科学领域:

分子生物学分子生物学
生物化学生物化学
遗传学是一个遗传学.

背景情况:

细菌的SOS反应涉及通过特定的裂变来禁用LexA抑制剂.
RecA蛋白在体内对LexA分裂至关重要,通过增强LexA的自我分裂活动,间接地作为共蛋白酶起作用.
类似的过程,lambda Cl抑制剂的裂变,导致prophage诱导,但发生的速度要慢得多.

研究的目的:

为了研究LexA抑制器自我切割的机制.
描述LexA C端片段的分子间裂变活动.
为了比较LexA和lambda Cl抑制剂在LexA基质上的酶活性.

主要方法:

描述一个分子间裂变反应.
使用LexA和lambda Cl抑制器碎片.
评估LexA基板上的切割效率.

主要成果:

发现LexA的C端片段作为一种酶,分裂其他LexA分子.
兰巴抑制剂的C端片段证明了效率高的LexA基质裂解,与LexA酶相似.
这表明,lambda Cl抑制剂的缓慢自我裂变率是由于其裂变部位与活性部位之间的相互作用较弱.

结论:

莱克斯A抑制剂具有其C端片段介导的固有分子间自我切割活性.
兰巴Cl抑制剂具有类似的裂变机制,突出显示保存的酶性质.
分裂速率的差异归因于活性部位-分裂部位相互作用的变化,为DNA修复和菌体调节提供了机理性的见解.

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