Effects of conserved residues and naturally occurring mutations on Mycobacterium tuberculosis RecG helicase activity
| Autor: | Håvard Homberset, Ephrem Debebe Zegeye, Per Eugen Kristiansen, Seetha V. Balasingham, Tone Tønjum, Jon K. Laerdahl |
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| Rok vydání: | 2014 |
| Předmět: |
Models
Molecular Protein Conformation DNA repair DNA Mutational Analysis Molecular Sequence Data Mutant Mutation Missense medicine.disease_cause Microbiology chemistry.chemical_compound medicine Holliday junction Amino Acid Sequence Gene Mutation biology Mutagenesis DNA Helicases Helicase Mycobacterium tuberculosis Molecular biology chemistry Biochemistry Mutagenesis Site-Directed biology.protein Mutant Proteins Physiology and Biochemistry Sequence Alignment DNA |
| Zdroj: | Microbiology. 160:217-227 |
| ISSN: | 1465-2080 1350-0872 |
| DOI: | 10.1099/mic.0.072140-0 |
| Popis: | RecG is a helicase that is conserved in nearly all bacterial species. The prototypicalEscherichia coliRecG promotes regression of stalled replication forks, participates in DNA recombination and DNA repair, and prevents aberrant replication.Mycobacterium tuberculosisRecG (RecGMtb) is a DNA-dependent ATPase that unwinds a variety of DNA substrates, although its preferred substrate is a Holliday junction. Here, we performed site-directed mutagenesis of selected residues in the wedge domain and motifs Q, I, Ib and VI of RecGMtb. Three of the 10 substitution mutations engineered were detected previously as naturally occurring SNPs in the gene encoding RecGMtb. Alanine substitution mutations at residues Q292, F286, K321 and R627 abolished the RecGMtbunwinding activity, whilst RecGMtbF99A, P285S and T408A mutants exhibited ~25–50 % lower unwinding activity than WT. We also found that RecGMtbbound ATP in the absence of a DNA cofactor. |
| Databáze: | OpenAIRE |
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