Nucleic Acids Research Advance Access originally published online on April 22, 2007
Nucleic Acids Research 2007 35(9):2825-2832; doi:10.1093/nar/gkm080
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Nucleic Acids Research, 2007, Vol. 35, No. 9 2825-2832
© 2007 The Author(s)
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.0/uk/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Structural Biology |
Solution structure of Domains IVa and V of the 
subunit of Escherichia coli DNA polymerase III and interaction with the 
subunit
Research School of Chemistry, Australian National University, Canberra ACT 0200, Australia
*To whom correspondence should be addressed. Tel: +61-2-61256507; Fax: +61-2-61250750; Email: gottfried.otting{at}anu.edu.au
Received October 19, 2006. Revised January 1, 2007. Accepted January 26, 2007.
The solution structure of the C-terminal Domain V of the 
subunit of E. coli DNA polymerase III was determined by nuclear magnetic resonance (NMR) spectroscopy. The fold is unique to subunits. Amino acid sequence conservation is pronounced for hydrophobic residues that form the structural core of the protein, indicating that the fold is representative for subunits from a wide range of different bacteria. The interaction between the polymerase subunits and 
was studied by NMR experiments where was incubated with full-length C-terminal domain (C16), and domains shortened at the C-terminus by 11 and 18 residues, respectively. The only interacting residues were found in the C-terminal 30-residue segment of , most of which is structurally disordered in free C16. Since the N- and C-termini of the structured core of C16 are located close to each other, this limits the possible distance between and the pentameric 
2
' clamp–loader complex and, hence, between the two subunits involved in leading- and lagging-strand DNA synthesis. Analysis of an N-terminally extended construct (C22) showed that C14 presents the only part of Domains IVa and V of which comprises a globular fold in the absence of other interaction partners.
Present address: Nicholas E. Dixon, Department of Chemistry, University of Wollongong, NSW 2522, Australia.