Modulating the pKaof a Tyrosine inKlenTaqDNA Polymerase that Is Crucial for Abasic Site Bypass by in Vivo Incorporation of a Non-canonical Amino Acid
| Autor: | Alexander Prokup, Andreas Marx, Alexander Deiters, Nina Blatter |
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| Rok vydání: | 2014 |
| Předmět: |
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Molecular DNA polymerase Mutant DNA replication Biochemistry fluorotyrosine abasic site Taq Polymerase Nucleotide AP site Tyrosine Molecular Biology chemistry.chemical_classification Molecular Structure biology Organic Chemistry Hydrogen Bonding protein engineering Protein engineering Hydrogen-Ion Concentration Amino acid chemistry ddc:540 biology.protein Molecular Medicine unnatural amino acid mutagenesis |
| Zdroj: | ChemBioChem. 15:1735-1737 |
| ISSN: | 1439-4227 |
| DOI: | 10.1002/cbic.201400051 |
| Popis: | It is estimated that about 10,000 abasic sites are formed per day per cell. Abasic sites impose a significant challenge for bypass synthesis by DNA polymerases. Recently, a tyrosine in KlenTaq DNA polymerase has been highlighted as being crucial for nucleotide selection opposite abasic sites. Structural data indicated a hydrogen bond between the tyrosine's hydroxy group and the N3 of an incoming ddATP opposite the abasic site. In order to further investigate abasic site bypass, we incorporated the unnatural amino acid 2,3,5-trifluorotyrosine at the position of the crucial tyrosine of KlenTaq DNA polymerase. Fluorine substitution at the tyrosine decreased the pka value of the tyrosine's hydroxy group and allowed its protonation state to be modulated. Single-nucleotide-incorporation experiments revealed reduced activity for the KlenTaq mutant compared to the wild-type when bypassing an abasic site analogue. The finding stresses the involvement of this tyrosine and its hydrogen bonding in abasic site bypass. |
| Databáze: | OpenAIRE |
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