突变型RecA蛋白在双链DNA解旋和同源配对方面的特定缺陷。

Specific defects in double-stranded DNA unwinding and homologous pairing of a mutant RecA protein.

作者信息

Kurumizaka H, Aihara H, Ikawa S, Shibata T

机构信息

Cellular and Molecular Biology Laboratory, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan.

出版信息

FEBS Lett. 2000 Jul 14;477(1-2):129-34. doi: 10.1016/s0014-5793(00)01781-6.

DOI:10.1016/s0014-5793(00)01781-6

PMID:10899323

Abstract

The DNA molecules bound to RecA filaments are extended 1.5-fold relative to B-form DNA. This extended DNA structure may be important in the recognition of homology between single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA). In this study, we show that the K286N mutation specifically impaired the dsDNA unwinding and homologous pairing activities of RecA, without an apparent effect on dsDNA binding itself. In contrast, the R243Q mutation caused defective dsDNA unwinding, due to the defective dsDNA binding of the C-terminal domain of RecA. These results provide new evidence that dsDNA unwinding is essential to homology recognition between ssDNA and dsDNA during homologous pairing.

摘要

与RecA细丝结合的DNA分子相对于B型DNA伸展了1.5倍。这种伸展的DNA结构可能在单链DNA（ssDNA）和双链DNA（dsDNA）之间的同源性识别中起重要作用。在本研究中，我们表明K286N突变特异性地损害了RecA的dsDNA解旋和同源配对活性，而对dsDNA自身结合没有明显影响。相比之下，R243Q突变导致dsDNA解旋缺陷，这是由于RecA C末端结构域的dsDNA结合缺陷所致。这些结果提供了新的证据，表明dsDNA解旋对于同源配对过程中ssDNA和dsDNA之间的同源性识别至关重要。