Single-molecule nanopositioning: structural transitions of a helicase-DNA complex during ATP hydrolysis.

ABSTRACT: The conformational states of Escherichia coli Rep helicase undergoing ATP hydrolysis while bound to a partial-duplex DNA (pdDNA) were studied using single-molecule FRET. Crystallographic studies showed that Rep bound to single-stranded DNA can exist in open and closed conformations that differ in the orientation of the 2B subdomain. FRET measurements between eight Rep mutants donor-labeled at different residues and pdDNA acceptor-labeled at the junction were conducted at each of the four nucleotide states. The positions of donor-labeled residues, based on crystal structure, and FRET measurements between these donor molecules and the acceptor fluorophore at the DNA junction were used to predict the most likely position for the DNA junction using a triangulation algorithm. These predicted ju

SUBMITTER: Balci H 

PROVIDER: S-EPMC3175085 | biostudies-literature | 2011 Aug

REPOSITORIES: biostudies-literature