Structural highlights
FunctionUNG_MIMIV Excises uracil residues from the DNA which can arise as a result of misincorporation of dUMP residues by DNA polymerase or due to deamination of cytosine. Publication Abstract from PubMedCytosine deamination induced by stresses or enzymatic catalysis converts deoxycytidine into deoxyuridine, thereby introducing a G to A mutation after DNA replication. Base-excision repair to correct uracil to cytosine is initiated by uracil-DNA glycosylase (UDG), which recognizes and eliminates uracil from DNA. Mimivirus, one of the largest known viruses, also encodes a distinctive UDG gene containing a long N-terminal domain (N-domain; residues 1-130) and a motif-I (residues 327-343), in addition to the canonical catalytic domain of family I UDGs (also called UNGs). To understand the structural and functional features of the additional segments, we have determined the crystal structure of UNG from Acanthamoeba polyphaga mimivirus (mvUNG). In the crystal structure of mvUNG, residues 95-130 in the N-domain bind to a hydrophobic groove in the catalytic domain, and motif-I forms a short beta-sheet with a positively charged surface near the active site. Circular dichroism spectra showed that residues 1-94 are in a random coil conformation. Deletion of the three additional fragments reduced the activity and thermal stability, compared to full-length mvUNG. The results suggested that the mvUNG N-domain and motif-I are required for its structural and functional integrity. Crystal structure of mimivirus uracil-DNA glycosylase.,Kwon E, Pathak D, Chang HW, Kim DY PLoS One. 2017 Aug 1;12(8):e0182382. doi: 10.1371/journal.pone.0182382., eCollection 2017. PMID:28763516[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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