Abstract
We report that Chlorella virus PBCV-1 encodes a 298-amino-acid ATP- dependent DNA ligase. The PBCV-1 enzyme is the smallest member of the covalent nucleotidyl transferase superfamily, which includes the ATP- dependent polynucleotide ligases and the GTP-dependent RNA capping enzymes. The specificity of PBCV-1 DNA ligase was investigated by using purified recombinant protein. The enzyme catalyzed efficient strand joining on a singly nicked DNA in the presence of magnesium and ATP (K(m), 75 μM). Other nucleoside triphosphates or deoxynucleoside triphosphates could not substitute for ATP. PBCV-1 ligase was unable to ligate across a 2-nucleotide gap and ligated poorly across a 1-nucleotide gap. A native gel mobility shift assay showed that PBCV-1 DNA ligase discriminated between nicked and gapped DNAs at the substrate-binding step. These findings underscore the importance of a properly positioned 3' OH acceptor terminus in substrate recognition and reaction chemistry.
Original language | English (US) |
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Pages (from-to) | 1931-1937 |
Number of pages | 7 |
Journal | Journal of virology |
Volume | 71 |
Issue number | 3 |
DOIs | |
State | Published - Mar 1997 |
ASJC Scopus subject areas
- Microbiology
- Immunology
- Insect Science
- Virology