1P045 Functional Analysis of a New Type I Antifreeze Protein from Barfin plaice, Liposetta pinnifasciata(01B. Protein : Structure & Function,Poster,The 52nd Annual Meeting of the Biophysical Society of Japan(BSJ2014))

Abstract

RecBCD, which contains two helicases and a nuclease, plays important roles in DNA digestion and repair. We directly traced the enzyme functional process at high spatial (a few nanometers) and temporal (~0.3 s) resolution with high-speed atomic force microscopy. At the beginning, RecBCD bound to the end of dsDNA, while the other end labeled with biotin was blocked by streptavidin. When ATP was added, RecBCD translocated and digested dsDNA. After the reaction stopped at Chi which is a regulatory eight-nucleotide DNA sequence for ~10 s, RecBCD restarted to translocate and generated ssDNA. The movement of RecBCD was much less vigorous than before the pause. Thus, the functional processes of RecBCD, including Chi sequence recognition have been successfully visualized.