5′-Single-stranded/duplex DNA junctions are loading sites for E. coli UvrD translocase
| Autor: | Taekjip Ha, Jeehae Park, Nasib K. Maluf, Haifeng Jia, Timothy M. Lohman, Eric J. Tomko |
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| Rok vydání: | 2010 |
| Předmět: |
DNA
Bacterial Models Molecular 5' Flanking Region 5' flanking region DNA Single-Stranded Plasma protein binding medicine.disease_cause Article General Biochemistry Genetics and Molecular Biology Substrate Specificity chemistry.chemical_compound Bacterial Proteins Escherichia coli medicine Translocase Amino Acid Sequence Binding site Molecular Biology Peptide sequence Binding Sites General Immunology and Microbiology biology Escherichia coli Proteins General Neuroscience DNA Helicases Helicase Protein Structure Tertiary Biochemistry chemistry Mutation biology.protein Biophysics DNA Protein Binding |
| Zdroj: | The EMBO Journal. 29:3826-3839 |
| ISSN: | 1460-2075 0261-4189 |
| DOI: | 10.1038/emboj.2010.242 |
| Popis: | Escherichia coli UvrD is a 3'-5' superfamily 1A helicase/translocase involved in a variety of DNA metabolic processes. UvrD can function either as a helicase or only as an single-stranded DNA (ssDNA) translocase. The switch between these activities is controlled in vitro by the UvrD oligomeric state; a monomer has ssDNA translocase activity, whereas at least a dimer is needed for helicase activity. Although a 3'-ssDNA partial duplex provides a high-affinity site for a UvrD monomer, here we show that a monomer also binds with specificity to DNA junctions possessing a 5'-ssDNA flanking region and can initiate translocation from this site. Thus, a 5'-ss-duplex DNA junction can serve as a high-affinity loading site for the monomeric UvrD translocase, whereas a 3'-ss-duplex DNA junction inhibits both translocase and helicase activity of the UvrD monomer. Furthermore, the 2B subdomain of UvrD is important for this junction specificity. This highlights a separation of helicase and translocase function for UvrD and suggests that a monomeric UvrD translocase can be loaded at a 5'-ssDNA junction when translocation activity alone is needed. |
| Databáze: | OpenAIRE |
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