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Publication Abstract from PubMed

DNA 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^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.