5Z3N image
Entry Detail
PDB ID:
5Z3N
Keywords:
Title:
Structure of large fragment of DNA Polymerase I from Thermus aquaticus Host-Guest complex with the unnatural base 5fC pair with dA
Biological Source:
Host Organism:
PDB Version:
Deposition Date:
2018-01-08
Release Date:
2018-11-21
Method Details:
Experimental Method:
Resolution:
1.91 Å
R-Value Free:
0.22
R-Value Work:
0.18
R-Value Observed:
0.18
Space Group:
P 31 2 1
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:DNA polymerase I, thermostable
Chain IDs:A
Chain Length:539
Number of Molecules:1
Biological Source:Thermus aquaticus
Polymer Type:polydeoxyribonucleotide
Description:DNA (5'-D(*GP*AP*CP*CP*AP*CP*GP*GP*CP*GP*CP*(DOC))-3')
Chain IDs:B
Chain Length:12
Number of Molecules:1
Biological Source:synthetic construct
Polymer Type:polydeoxyribonucleotide
Description:DNA (5'-D(*AP*AP*AP*CP*GP*GP*CP*GP*CP*CP*GP*(5FC)P*GP*GP*TP*C)-3')
Chain IDs:C
Chain Length:16
Number of Molecules:1
Biological Source:synthetic construct
Primary Citation
Unnatural Cytosine Bases Recognized as Thymines by DNA Polymerases by the Formation of the Watson-Crick Geometry.
Angew. Chem. Int. Ed. Engl. 58 130 133 (2019)
PMID: 30407705 DOI: 10.1002/anie.201807845

Abstact

The emergence of unnatural DNA bases provides opportunities to demystify the mechanisms by which DNA polymerases faithfully decode chemical information on the template. It was previously shown that two unnatural cytosine bases (termed "M-fC" and "I-fC"), which are chemical labeling adducts of the epigenetic base 5-formylcytosine, can induce C-to-T transition during DNA amplification. However, how DNA polymerases recognize such unnatural cytosine bases remains enigmatic. Herein, crystal structures of unnatural cytosine bases pairing to dA/dG in the KlenTaq polymerase-host-guest complex system and pairing to dATP in the KlenTaq polymerase active site were determined. Both M-fC and I-fC base pair with dA/dATP, but not with dG, in a Watson-Crick geometry. This study reveals that the formation of the Watson-Crick geometry, which may be enabled by the A-rule, is important for the recognition of unnatural cytosines.

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