6x74
Rev1 Mg2+-facilitated Product Complex with no monophosphates
Structural highlights
FunctionREV1_YEAST Deoxycytidyl transferase involved in DNA repair. Transfers a dCMP residue from dCTP to the 3'-end of a DNA primer in a template-dependent reaction. May assist in the first step in the bypass of abasic lesions by the insertion of a nucleotide opposite the lesion. Required for normal induction of mutations by physical and chemical agents. Involved in mitochondrial DNA mutagenesis.[1] [2] [3] Publication Abstract from PubMedDuring DNA replication, replicative DNA polymerases may encounter DNA lesions, which can stall replication forks. One way to prevent replication fork stalling is through the recruitment of specialized translesion synthesis (TLS) polymerases that have evolved to incorporate nucleotides opposite DNA lesions. Rev1 is a specialized TLS polymerase that bypasses abasic sites, as well as minor-groove and exocyclic guanine adducts. Lesion bypass is accomplished using a unique protein-template mechanism in which the templating base is evicted from the DNA helix and the incoming dCTP hydrogen bonds with an arginine side chain of Rev1. To understand the protein-template mechanism at an atomic level, we employed a combination of time-lapse X-ray crystallography, molecular dynamics simulations, and DNA enzymology on the Saccharomyces cerevisiae Rev1 protein. We find that Rev1 evicts the templating base from the DNA helix prior to binding the incoming nucleotide. Binding the incoming nucleotide changes the conformation of the DNA substrate to orient it for nucleotidyl transfer, although this is not coupled to large structural changes in Rev1 like those observed with other DNA polymerases. Moreover, we found that following nucleotide incorporation, Rev1 converts the pyrophosphate product to two monophosphates, which drives the reaction in the forward direction and prevents pyrophosphorolysis. Following nucleotide incorporation, the hydrogen bonds between the incorporated nucleotide and the arginine side chain are broken, but the templating base remains extrahelical. These postcatalytic changes prevent potentially mutagenic processive synthesis by Rev1 and facilitate dissociation of the DNA product from the enzyme. Visualizing Rev1 catalyze protein-template DNA synthesis.,Weaver TM, Cortez LM, Khoang TH, Washington MT, Agarwal PK, Freudenthal BD Proc Natl Acad Sci U S A. 2020 Oct 13;117(41):25494-25504. doi:, 10.1073/pnas.2010484117. Epub 2020 Sep 30. PMID:32999062[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
| ||||||||||||||||||||
