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Professor Nick E Dixon

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Full-Text Articles in Social and Behavioral Sciences

Structure Of The Theta Subunit Of Escherichia Coli Dna Polymerase Iii In Complex With The Epsilon Subunit, Max A Keniry, Ah-Young Park, Elisabeth A. Owen, Samir M. Hamdan, Guido Pintacuda, Gottfried Otting, Nicholas E. Dixon Jul 2013

Structure Of The Theta Subunit Of Escherichia Coli Dna Polymerase Iii In Complex With The Epsilon Subunit, Max A Keniry, Ah-Young Park, Elisabeth A. Owen, Samir M. Hamdan, Guido Pintacuda, Gottfried Otting, Nicholas E. Dixon

Professor Nick E Dixon

The catalytic core of Escherichia coli DNA polymerase III contains three tightly associated subunits, the α, ε, and θ subunits. The θ subunit is the smallest and least understood subunit. The three-dimensional structure of θ in a complex with the unlabeled N-terminal domain of the ε subunit, ε186, was determined by multidimensional nuclear magnetic resonance spectroscopy. The structure was refined using pseudocontact shifts that resulted from inserting a lanthanide ion (Dy3+, Er3+, or Ho3+) at the active site of ε186. The structure determination revealed a three-helix bundle fold that is similar to the solution structures of θ in a methanol-water …


Proofreading Exonuclease On A Tether: The Complex Between The E. Coli Dna Polymerase Iii Subunits Α, Ε, Θ And Β Reveals A Highly Flexible Arrangement Of The Proofreading Domain, Kiyoshi Ozawa, Nicholas P. Horan, Andrew Robinson, Hiromasa Yagi, Flynn R. Hill, Slobodan Jergic, Zhi-Qiang Xu, Karin V. Loscha, Nan Li, Moeava Tehei, Aaron J. Oakley, Gottfried Otting, Thomas Huber, Nicholas E. Dixon Jul 2013

Proofreading Exonuclease On A Tether: The Complex Between The E. Coli Dna Polymerase Iii Subunits Α, Ε, Θ And Β Reveals A Highly Flexible Arrangement Of The Proofreading Domain, Kiyoshi Ozawa, Nicholas P. Horan, Andrew Robinson, Hiromasa Yagi, Flynn R. Hill, Slobodan Jergic, Zhi-Qiang Xu, Karin V. Loscha, Nan Li, Moeava Tehei, Aaron J. Oakley, Gottfried Otting, Thomas Huber, Nicholas E. Dixon

Professor Nick E Dixon

A complex of the three (αεθ) core subunits and the β2 sliding clamp is responsible for DNA synthesis by Pol III, the Escherichia coli chromosomal DNA replicase. The 1.7 Å crystal structure of a complex between the PHP domain of α (polymerase) and the C-terminal segment of ε (proofreading exonuclease) subunits shows that ε is attached to α at a site far from the polymerase active site. Both α and ε contain clamp-binding motifs (CBMs) that interact simultaneously with β2 in the polymerization mode of DNA replication by Pol III. Strengthening of both CBMs enables isolation of stable αεθ:β2 complexes. …


Flexibility Revealed By The 1.85 Å Crystal Structure Of The Β Sliding-Clamp Subunit Of Escherichia Coli Dna Polymerase Iii, Aaron J. Oakley, Pavel Prosselkov, Gene Wijffels, Jennifer L. Beck, Matthew Cj Wilce, Nicholas E. Dixon Jul 2013

Flexibility Revealed By The 1.85 Å Crystal Structure Of The Β Sliding-Clamp Subunit Of Escherichia Coli Dna Polymerase Iii, Aaron J. Oakley, Pavel Prosselkov, Gene Wijffels, Jennifer L. Beck, Matthew Cj Wilce, Nicholas E. Dixon

Professor Nick E Dixon

The subunit of the Escherichia coli replicative DNA polymerase III holoenzyme is the sliding clamp that interacts with the (polymerase) subunit to maintain the high processivity of the enzyme. The protein is a ring-shaped dimer of 40.6 kDa subunits whose structure has previously been determined at a resolution of 2.5 Å [Kong et al. (1992), Cell, 69, 425-437]. Here, the construction of a new plasmid that directs overproduction of to very high levels and a simple procedure for large-scale purification of the protein are described. Crystals grown under slightly modified conditions diffracted to beyond 1.9 Å at 100 K at …