The dTTPase mechanism of T7 DNA helicase resembles the binding change mechanism of the F1-ATPase

Manju M Hingorani; M. Todd Washington; Kristen C Moore; Smita S Patel

doi:10.1073/pnas.94.10.5012

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The dTTPase mechanism of T7 DNA helicase resembles the binding change mechanism of the F1-ATPase

Journal article

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The dTTPase mechanism of T7 DNA helicase resembles the binding change mechanism of the F1-ATPase

Manju M Hingorani, M. Todd Washington, Kristen C Moore and Smita S Patel

Proceedings of the National Academy of Sciences - PNAS, Vol.94(10), pp.5012-5017

05/13/1997

DOI: 10.1073/pnas.94.10.5012

PMID: 9144181

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https://www.ncbi.nlm.nih.gov/pmc/articles/24622View

Open Access

Abstract

Bacteriophage T7 DNA helicase is a ring-shaped hexamer that catalyzes duplex DNA unwinding using dTTP hydrolysis as an energy source. Of the six potential nucleotide binding sites on the hexamer, we have found that three are noncatalytic sites and three are catalytic sites. The noncatalytic sites bind nucleotides with a high affinity, but dTTPs bound to these sites do not dissociate or hydrolyze through many dTTPase turnovers at the catalytic sites. The catalytic sites show strong cooperativity which leads to sequential binding and hydrolysis of dTTP. The elucidated dTTPase mechanism of the catalytic sites of T7 helicase is remarkably similar to the binding change mechanism of the ATP synthase. Based on the similarity, a general mechanism for hexameric helicases is proposed. In this mechanism, an F1-ATPase-like rotational movement around the single-stranded DNA, which is bound through the central hole of the hexamer, is proposed to lead to unidirectional translocation along single-stranded DNA and duplex DNA unwinding.

Biological Sciences

Details

Title: Subtitle: The dTTPase mechanism of T7 DNA helicase resembles the binding change mechanism of the F1-ATPase
Creators: Manju M Hingorani - Department of Biochemistry, Ohio State University, 484 West 12th Avenue, Columbus, OH 43210
M. Todd Washington - Department of Biochemistry, Ohio State University, 484 West 12th Avenue, Columbus, OH 43210
Kristen C Moore - Department of Biochemistry, Ohio State University, 484 West 12th Avenue, Columbus, OH 43210
Smita S Patel - Department of Biochemistry, Ohio State University, 484 West 12th Avenue, Columbus, OH 43210
Resource Type: Journal article
Publication Details: Proceedings of the National Academy of Sciences - PNAS, Vol.94(10), pp.5012-5017
DOI: 10.1073/pnas.94.10.5012
PMID: 9144181
NLM abbreviation: Proc Natl Acad Sci U S A
ISSN: 0027-8424
eISSN: 1091-6490
Publisher: National Academy of Sciences
Language: English
Date published: 05/13/1997
Academic Unit: Radiation Oncology; Biochemistry and Molecular Biology
Record Identifier: 9984025259902771

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