Journal
JOURNAL OF BIOLOGICAL CHEMISTRY
Volume 276, Issue 22, Pages 19182-19189Publisher
AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
DOI: 10.1074/jbc.M100592200
Keywords
-
Categories
Funding
- NIGMS NIH HHS [GM38839] Funding Source: Medline
Ask authors/readers for more resources
The beta sliding clamp encircles the primer-template and tethers DNA polymerase III holoenzyme to DNA for processive replication of the Escherichia coli genome. The clamp is formed via hydrophobic and ionic interactions between two semicircular beta monomers, This report demonstrates that the beta dimer is a stable closed ring and is not monomerized when the gamma complex clamp loader (gamma (3)delta (1)delta (1)chi (1)psi (1)) assembles the beta ring around DNA. delta is the subunit of the gamma complex that binds beta and opens the ring; it also does not appear to monomerize beta. Point mutations were introduced at the beta dimer interface to test its structural integrity and gain insight into its interaction with delta, Mutation of two residues at the dimer interface of beta, I272A/L273A, yields a stable beta monomer, We find that delta binds the beta monomer mutant at least 50-fold tighter than the beta dimer. These findings suggest that when delta interacts with the p clamp, it binds one beta subunit with high affinity and utilizes some of that binding energy to perform work on the dimeric clamp, probably cracking one dimer interface open.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available