Proliferating cell nuclear antigen uses two distinct modes to move along DNA

Authors

Anna B. Kochaniak, Harvard Medical School
Satoshi Habuchi, Harvard Medical School
Joseph J. Loparo, Harvard Medical School
Debbie J. Chang, Stanford University
Karlene A. Cimprich, Stanford University
Johannes C. Walter, Harvard Medical School
Antoine M. van Oijen, Harvard Medical SchoolFollow

RIS ID

94075

Publication Details

Kochaniak, A. B., Habuchi, S., Loparo, J. J., Chang, D. J., Cimprich, K. A., Walter, J. C. & van Oijen, A. M. (2009). Proliferating cell nuclear antigen uses two distinct modes to move along DNA. Journal of Biological Chemistry, 284 (26), 17700-17710.

Abstract

Proliferating cell nuclear antigen (PCNA) plays an important role in eukaryotic genomic maintenance by topologically binding DNA and recruiting replication and repair proteins. The ring-shaped protein forms a closed circle around double-stranded DNA and is able to move along the DNA in a random walk. The molecular nature of this diffusion process is poorly understood. We use single-molecule imaging to visualize the movement of individual, fluorescently labeled PCNA molecules along stretched DNA. Measurements of diffusional properties as a function of viscosity and protein size suggest that PCNA moves along DNA using two different sliding modes. Most of the time, the clamp moves while rotationally tracking the helical pitch of the DNA duplex. In a less frequently used second mode of diffusion, the movement of the protein is uncoupled from the helical pitch, and the clamp diffuses at much higher rates.