Holliday junction is a universal intermediate in DNA homologous recombination. In prokaryotes, RuvA, RuvB and RuvC proteins play crucial roles in the late stage of the recombination through mediating ATP-dependent branch migration and resolution of Holliday junction. The specific binding of the RuvA tetramer to the junction DNA allows RuvB to assemble on DNA as a hexameric ring. To clarify how Holliday junction is recognized by RuvA, we determined the crystal structure of the RuvA-Holliday junction complex. The structure reveals the recognition mechanism specific for the junction structure. It also disclosed the positive role of RuvA in rearranging base pairs at the junction center during branch migration.
It is widely believed that myosin generates force by swinging its light-chain binding domain (lever arm) on the motor domain, which is affixed firmly onto actin via stereospecific hydrophobic interactions. However, recent results suggest that the events taking place at the actin-myosin interface are more dynamic than previously considered. This brief review discusses some of the results which suggest such dynamic nature of actin-myosin interface in relation to the conventional understanding.
This report discusses how one can argue the origin of a symbol in animal behaviors, with respect to experiments and models. The results suggest that the frame-problem resulting in the power-law positively plays a role in the origin of a symbol.