Activation of human meiosis-specific recombinase Dmc1 by Ca2+

Dmitry V. Bugreev, Efim I. Golub, Alicja Z. Stasiak, Andrzej Stasiak, Alexander V. Mazin

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70 Scopus citations


Rad51 and its meiotic homolog Dmc1 are key proteins of homologous recombination in eukaryotes. These proteins form nucleoprotein complexes on single-stranded DNA that promote a search for homology and that perform DNA strand exchange, the two essential steps of genetic recombination. Previously, we demonstrated that Ca2+ greatly stimulates the DNA strand exchange activity of human (h) Rad51 protein (Bugreev, D. V., and Mazin, A. V. (2004) Proc. Natl. Acad. Sci. U. S. A. 101, 9988-9993). Here, we show that the DNA strand exchange activity of hDmc1 protein is also stimulated by Ca2+. However, the mechanism of stimulation of hDmc1 protein appears to be different from that of hRad51 protein. In the case of hRad51 protein, Ca2+ acts primarily by inhibiting its ATPase activity, thereby preventing self-conversion into an inactive ADP-bound complex. In contrast, we demonstrate that hDmc1 protein does not self-convert into a stable ADP-bound complex. The results indicate that activation of hDmc1 is mediated through conformational changes induced by free Ca2+ ion binding to a protein site that is distinct from the Mg2+-ATP-binding center. These conformational changes are manifested by formation of more stable filamentous hDmc1-single-stranded DNA complexes. Our results demonstrate a universal role of Ca2+ in stimulation of mammalian DNA strand exchange proteins and reveal diversity in the mechanisms of this stimulation.

Original languageEnglish (US)
Pages (from-to)26886-26895
Number of pages10
JournalJournal of Biological Chemistry
Issue number29
StatePublished - Jul 22 2005
Externally publishedYes

ASJC Scopus subject areas

  • Molecular Biology
  • Biochemistry
  • Cell Biology


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