Rusche J R, Konigsberg W, Howard-Flanders P
J Biol Chem. 1985 Jan 25;260(2):949-55.
In this paper we describe the partial proteolytic digestion of recA proteins from Escherichia coli and Proteus mirabilis and the production and isolation of truncated recA polypeptides. A proteolytic fragment of the P. mirabilis recA protein bound single-strand DNA and ATP normally but has altered duplex DNA binding properties. This protein was shown to initiate but not complete DNA strand transfer from a DNA duplex to a complementary single strand. The product of the E. coli recA1 allele bound but could not hydrolyze ATP and the protein bound single-strand but not double-strand DNA. This protein did not appear to initiate the transfer of a strand from a linear duplex to a single-strand circle and inhibited the wild-type recA protein from performing strand transfer. We report that recA protein binds linear duplex DNA in a manner that enhances the rate of ligation by T4 DNA ligase. When heterologous single-strand DNA was added in addition to the duplex DNA large stable aggregates of protein and DNA were formed that could easily be sedimented from solution.
在本文中，我们描述了来自大肠杆菌和奇异变形杆菌的RecA蛋白的部分蛋白酶解消化过程，以及截短的RecA多肽的产生和分离。奇异变形杆菌RecA蛋白的一个蛋白酶解片段能正常结合单链DNA和ATP，但其二聚体DNA结合特性发生了改变。该蛋白被证明能启动但不能完成从DNA双链到互补单链的DNA链转移。大肠杆菌recA1等位基因的产物能结合但不能水解ATP，且该蛋白能结合单链DNA但不能结合双链DNA。这种蛋白似乎不能启动从线性双链到单链环的链转移，并抑制野生型RecA蛋白进行链转移。我们报道，RecA蛋白以一种提高T4 DNA连接酶连接速率的方式结合线性双链DNA。当除双链DNA外还加入异源单链DNA时，会形成蛋白质和DNA的大的稳定聚集体，这些聚集体很容易从溶液中沉淀出来。
