Linked Life Data

16844179

Source:http://linkedlifedata.com/resource/pubmed/id/16844179

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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2006-9-1
pubmed:abstractText
Mimivirus, a parasite of Acanthamoeba polyphaga, is the largest DNA virus known; it encodes a cornucopia of proteins with imputed functions in DNA replication, modification, and repair. Here we produced, purified, and characterized mimivirus DNA ligase (MimiLIG), an NAD+-dependent nick joining enzyme homologous to bacterial LigA and entomopoxvirus DNA ligase. MimiLIG is a 636-aa polypeptide composed of an N-terminal NAD+ specificity module (domain Ia), linked to nucleotidyltransferase, OB-fold, helix-hairpin-helix, and BRCT domains, but it lacks the tetracysteine Zn-binding module found in all bacterial LigA enzymes. MimiLIG requires conserved domain Ia residues Tyr36, Asp46, Tyr49, and Asp50 for its initial reaction with NAD+ to form the ligase-AMP intermediate, but not for the third step of phosphodiester formation at a preadenylylated nick. MimiLIG differs from bacterial LigA enzymes in that its activity is strongly dependent on the C-terminal BRCT domain, deletion of which reduced its specific activity in nick joining by 75-fold without affecting the ligase adenylylation step. The DeltaBRCT mutant of MimiLIG was impaired in sealing at a preadenylylated nick. We propose that eukaryal DNA viruses acquired the NAD+-dependent ligases by horizontal transfer from a bacterium and that MimiLIG predates entomopoxvirus ligase, which lacks both the tetracysteine and BRCT domains. We speculate that the dissemination of NAD+-dependent ligase from bacterium to eukaryotic virus might have occurred within an amoebal host.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0042-6822
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
353
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
133-43
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
Characterization of mimivirus NAD+-dependent DNA ligase.
pubmed:affiliation
Molecular Biology Program, Sloan-Kettering Institute, New York, NY 10021, USA.
pubmed:publicationType
Journal Article