6drt
From Proteopedia
Crystal structure of the processivity clamp GP45 complexed with recognition peptide of ligase from bacteriophage T4
Structural highlights
FunctionCLAMP_BPT4 Sliding clamp that encircles the genomic DNA and links the DNA polymerase to the template to control the processivity of DNA synthesis. Responsible for tethering the catalytic subunit of DNA polymerase to DNA during high-speed replication (PubMed:10535942). Interaction with the sliding-clamp-loader opens the sliding clamp so that it can be loaded around the DNA template (PubMed:22194570). During transcription, encircles the DNA and tethers host RNA polymerase (RNAP) to it (PubMed:33602900).[HAMAP-Rule:MF_04161][1] [2] [3] Publication Abstract from PubMedDNA ligases play essential roles in DNA replication and repair. Bacteriophage T4 DNA ligase is the first ATP-dependent ligase enzyme to be discovered and is widely used in molecular biology, but its structure remained unknown. Our crystal structure of T4 DNA ligase bound to DNA shows a compact alpha-helical DNA-binding domain (DBD), nucleotidyl-transferase (NTase) domain, and OB-fold domain, which together fully encircle DNA. The DBD of T4 DNA ligase exhibits remarkable structural homology to the core DNA-binding helices of the larger DBDs from eukaryotic and archaeal DNA ligases, but it lacks additional structural components required for protein interactions. T4 DNA ligase instead has a flexible loop insertion within the NTase domain, which binds tightly to the T4 sliding clamp gp45 in a novel alpha-helical PIP-box conformation. Thus, T4 DNA ligase represents a prototype of the larger eukaryotic and archaeal DNA ligases, with a uniquely evolved mode of protein interaction that may be important for efficient DNA replication. T4 DNA ligase structure reveals a prototypical ATP-dependent ligase with a unique mode of sliding clamp interaction.,Shi K, Bohl TE, Park J, Zasada A, Malik S, Banerjee S, Tran V, Li N, Yin Z, Kurniawan F, Orellana K, Aihara H Nucleic Acids Res. 2018 Aug 29. pii: 5085977. doi: 10.1093/nar/gky776. PMID:30169742[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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