DNA-induced conformational changes in RecA protein. Evidence for structural heterogeneity among nucleoprotein filaments and implications for homologous pairing.

摘要: We have used circular dichroism as a probe to characterize the solution conformational changes in RecA protein upon binding DNA. This approach revealed that acquires significant amounts of alpha-helix interaction with These observations, consistent data from crystal structure (Story, R. M., Weber, I., and Steitz, T. (1992) Nature 355, 318-325), support notion some basic domains including DNA motifs are unstructured might contribute formation alpha-helix. A comparison nucleoprotein filaments comprised variety substrates important structural heterogeneity. The most difference was observed poly(dG). poly(dC) related polymers, rich GC sequences, which induced minimal protein. magnitude induction protein, occurred concomitant production ternary complexes, 2-fold higher homologous than heterologous duplex Most importantly, stimulation ATP hydrolysis by high salt coincided differences provide basis for thinking about biochemical transitions experiences during formal steps presynapsis, recognition, alignment sequences.