In selecting ssDNA over dsDNA, the RAD51 DNA strand exchange protein has to overcome the entropy associated with straightening of single-strand DNA upon nucleoprotein filament formation. New work in The EMBO Journal (Paoletti et al, 2020), combined biophysical analysis of the RAD51-ssDNA interaction with mathematical modeling to show that the flexibility of DNA positively correlates with nucleation and extension of the RAD51 nucleoprotein filament and that the entropic penalty associated with restricting ssDNA flexibility is offset by a strong RAD51-RAD51 interaction within the nucleoprotein filament.

中文翻译：

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RAD51在单链和双链DNA之间的区分：灵活性和焓问题。

在选择ssDNA而不是dsDNA时，RAD51 DNA链交换蛋白必须克服与核蛋白细丝形成后单链DNA的拉直相关的熵。EMBO Journal的新工作（Paoletti等，2020）将RAD51-ssDNA相互作用的生物物理分析与数学模型相结合，显示出DNA的灵活性与RAD51核蛋白丝的成核和延伸呈正相关，并且与熵相关。限制ssDNA柔韧性的是被核蛋白丝中强烈的RAD51-RAD51相互作用抵消的。