Mycobacterial DNA polymerase I: Activities and crystal structures of the POL domain as apoenzyme and in complex with a DNA primer-template and of the full-length FEN/EXO-POL enzyme Journal Article
| Authors: | Ghosh, S.; Goldgur, Y.; Shuman, S. |
| Article Title: | Mycobacterial DNA polymerase I: Activities and crystal structures of the POL domain as apoenzyme and in complex with a DNA primer-template and of the full-length FEN/EXO-POL enzyme |
| Abstract: | Mycobacterial Pol1 is a bifunctional enzyme composed of an N-terminal DNA flap endonuclease/5' exonuclease domain (FEN/EXO) and a C-terminal DNA polymerase domain (POL). Here we document additional functions of Pol1: FEN activity on the flap RNA strand of an RNA:DNA hybrid and reverse transcriptase activity on a DNA-primed RNA template. We report crystal structures of the POL domain, as apoenzyme and as ternary complex with 3'-dideoxy-terminated DNA primer-template and dNTP. The thumb, palm, and fingers subdomains of POL form an extensive interface with the primer-template and the triphosphate of the incoming dNTP. Progression from an open conformation of the apoenzyme to a nearly closed conformation of the ternary complex entails a disordered-to-ordered transition of several segments of the thumb and fingers modules and an inward motion of the fingers subdomain-especially the O helix-to engage the primer-template and dNTP triphosphate. Distinctive structural features of mycobacterial Pol1 POL include a manganese binding site in the vestigial 3' exonuclease subdomain and a non-catalytic water-bridged magnesium complex at the protein-DNA interface. We report a crystal structure of the bifunctional FEN/EXO-POL apoenzyme that reveals the positions of two active site metals in the FEN/EXO domain. © The Author(s) 2020. Published by Oxford University Press on behalf of Nucleic Acids Research. |
| Journal Title: | Nucleic Acids Research |
| Volume: | 48 |
| Issue: | 6 |
| ISSN: | 0305-1048 |
| Publisher: | Oxford University Press |
| Date Published: | 2020-04-06 |
| Start Page: | 3165 |
| End Page: | 3180 |
| Language: | English |
| DOI: | 10.1093/nar/gkaa075 |
| PUBMED: | 32034423 |
| PROVIDER: | scopus |
| PMCID: | PMC7102940 |
| DOI/URL: | |
| Notes: | Article -- Export Date: 1 May 2020 -- Source: Scopus |
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