IONIC INHIBITION OF FORMATION OF RECA NUCLEOPROTEIN NETWORKS BLOCKS HOMOLOGOUS PAIRING
IONIC INHIBITION OF FORMATION OF RECA NUCLEOPROTEIN NETWORKS BLOCKS HOMOLOGOUS PAIRING
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DOI：
10.1073/pnas.82.17.5646
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发表时间：
1985-01-01
影响因子：
11.1
通讯作者：
RADDING, CM
中科院分区：
文献类型：
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作者：
CHOW, SA;RADDING, CM
有利于RecA蛋白完全包裹单链DNA的条件促进了这些突触前细丝与裸双链DNA的结合，在同源配对发生之前形成大的核蛋白网络。这些RecA核蛋白网络几乎隔离了反应混合物中的所有DNA。在RecA突触前丝形成的次优条件下，RecA- dna网络的形成和随后的关节分子的形成对过量ATP或焦磷酸的抑制很敏感，当这些在突触期间添加时。同源配对的速率与抑制网络形成的程度直接相关。在突触过程中加入的各种多价阳离子恢复了网络的形成和同源分子的配对。这些观察结果支持了核蛋白网络是突触中间体的观点，通过RecA蛋白促进DNA分子的连接和随后的同源性的过程搜索。此外，多价阴离子的抑制和多价阳离子的恢复表明，负电荷排斥抑制裸双工DNA与合成前细丝的结合。
Conditions that favor the complete coating of single-stranded DNA by RecA protein promote the association of these presynaptic filaments with naked double-stranded DNA to form large nucleoprotein networks before homologous pairing occurs. These RecA nucleoprotein networks sequester virtually all of the DNA in the reaction mixture. Conditions that are suboptimal for the formation of the RecA presynaptic filament rendered both the formation of RecA-DNA networks and the subsequent formation of joint molecules sensitive to inhibition by excess ATP or by pyrophosphate when these were added during synapsis. The rate of homologous pairing was directly related to the degree of inhibition of network formation. Various multivalent cations added during synapsis restored both the formation of networks and the pairing of homologous molecules. These observations support the view that the nucleoprotein network is a synaptic intermediate by means of which RecA protein facilitates the conjunction of DNA molecules and the subsequent processive search for homology. Inhibition by multivalent anions and restoration by mutlivalent cations suggests in addition, that negative charge repulsion inhibits the binding of naked duplex DNA to presynatic filaments.