Biochemical analysis of human PIF1 helicase and functions of its N-terminal domain.

ABSTRACT: The evolutionary conserved PIF1 DNA helicase family appears to have largely nonoverlapping cellular functions. To better understand the functions of human PIF1, we investigated biochemical properties of this protein. Analysis of single-stranded (ss) DNA-dependent ATPase activity revealed nonstructural ssDNA to greatly stimulate ATPase activity due to a high affinity for PIF1, even though PIF1 preferentially unwinds forked substrates. This suggests that PIF1 needs a ssDNA region for loading and a forked structure for translocation entrance into a double strand region. Deletion analysis demonstrated novel functions of a unique N-terminal portion, named the PIF1 N-terminal (PINT) domain. When the PINT domain was truncated, apparent affinity for ssDNA and unwinding activity were much reduced,

SUBMITTER: Gu Y 

PROVIDER: S-EPMC2577353 | biostudies-literature | 2008 Nov

REPOSITORIES: biostudies-literature