On the Unwinding of Dna.
نویسندگان
چکیده
منابع مشابه
DNA unwinding by replication protein A is a property of the 70 kDa subunit and is facilitated by phosphorylation of the 32 kDa subunit.
Replication protein A (RP-A) is a heterotrimeric single-stranded DNA binding protein with important functions in DNA replication, DNA repair and DNA recombination. We have found that RP-A from calf thymus can unwind DNA in the absence of ATP and MgCl2, two essential cofactors for bona fide DNA helicases (Georgaki, A., Strack, B., Podust, V. and Hübscher, U. FEBS Lett. 308, 240-244, 1992). DNA u...
متن کاملEscherichia coli DNA helicase II (uvrD gene product) catalyzes the unwinding of DNA.RNA hybrids in vitro.
DNA helicase II is a well-characterized Escherichia coli enzyme capable of unwinding duplex DNA and known to be involved in both methyl-directed mismatch repair and excision repair of pyrimidine dimers. Here it is shown that this enzyme also catalyzes the ATP-dependent unwinding of a DNA.RNA hybrid consisting of a radioactively labeled RNA molecule annealed on M13 single-stranded DNA. The DNA.R...
متن کاملSingle-molecule visualization of RecQ helicase reveals DNA melting, nucleation, and assembly are required for processive DNA unwinding.
DNA helicases are motor proteins that unwind double-stranded DNA (dsDNA) to reveal single-stranded DNA (ssDNA) needed for many biological processes. The RecQ helicase is involved in repairing damage caused by DNA breaks and stalled replication forks via homologous recombination. Here, the helicase activity of RecQ was visualized on single molecules of DNA using a fluorescent sensor that directl...
متن کاملEvidence for a functional dimeric form of the PcrA helicase in DNA unwinding
PcrA helicase, a member of the superfamily 1, is an essential enzyme in many bacteria. The first crystal structures of helicases were obtained with PcrA. Based on structural and biochemical studies, it was proposed and then generally believed that PcrA is a monomeric helicase that unwinds DNA by an inchworm mechanism. But a functional state of PcrA from unwinding kinetics studies has been lacki...
متن کاملSingle-Molecule Studies Reveal Dynamics of DNA Unwinding by the Ring-Shaped T7 Helicase
Helicases are molecular motors that separate DNA strands for efficient replication of genomes. We probed the kinetics of individual ring-shaped T7 helicase molecules as they unwound double-stranded DNA (dsDNA) or translocated on single-stranded DNA (ssDNA). A distinctive DNA sequence dependence was observed in the unwinding rate that correlated with the local DNA unzipping energy landscape. The...
متن کاملSteric exclusion and wrapping of the excluded DNA strand occurs along discrete external binding paths during MCM helicase unwinding
The minichromosome maintenance (MCM) helicase complex is essential for the initiation and elongation of DNA replication in both the eukaryotic and archaeal domains. The archaeal homohexameric MCM helicase from Sulfolobus solfataricus serves as a model for understanding mechanisms of DNA unwinding. In this report, the displaced 5'-tail is shown to provide stability to the MCM complex on DNA and ...
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عنوان ژورنال:
- Proceedings of the National Academy of Sciences of the United States of America
دوره 42 7 شماره
صفحات -
تاریخ انتشار 1956