HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

J. Biol. Chem., Vol. 277, Issue 12, 9741-9748, March 22, 2002

This Article Full Text Full Text (PDF) All Versions of this Article: 277/12/9741    most recent M111916200v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Arosio, D. Articles by Vindigni, A. Search for Related Content PubMed PubMed Citation Articles by Arosio, D. Articles by Vindigni, A. Social Bookmarking                      What's this?

Studies on the Mode of Ku Interaction with DNA^*

Daniele Arosio, Sheng Cui, Claudia Ortega, Miroslav Chovanec^§¶, Stefania Di Marco, Giancarlo Baldini^**, Arturo Falaschi, and Alessandro Vindigni

From the  International Centre for Genetic Engineering and Biotechnology, Padriciano, 99, Trieste I-34012, Italy, the ^§ Genome Damage and Stability Unit, University of Sussex, Falmer, Brighton, East Sussex BN1 9RR, United Kingdom, the  Istituto di Ricerche di Biologia Molecolare, P. Angeletti SpA, Pomezia, Rome 00040, Italy, and the ^** Dipartimento di Fisica, Universita' di Milano-Bicocca, Milano 20126, Italy

The Ku heterodimer plays a central role in non-homologous end-joining. The binding of recombinant Ku to DNA has been investigated by dynamic light scattering, double-filter binding, fluorescence spectroscopy, and band shift assays. The hydrodynamic radius of Ku in solution is 5.2 nm and does not change when a 25-bp double-strand DNA (dsDNA) fragment (D25) is added, indicating that only one Ku molecule binds to a 25-bp fragment. The dissociation constant (k_d) for the binding to D25 is 3.8 ± 0.9 nM. If both ends of the substrate are closed with hairpin loops, Ku is still able to bind with little change in the k_d. The k_d is not affected by ATP, Mg²⁺, or ionic strength. However, the addition of bovine serum albumin decreases the k_d by 2-fold. DNA substrates of 50 bp can bind two Ku molecules, whereas three molecules are bound to a 75-bp substrate. Data analysis with the Hill equation yields a value of the Hill coefficient (n) close to 1, and the k_d values for the binding of Ku to both ends of these substrates are the same. Thus, we demonstrate that there is no cooperative interaction among the Ku heterodimers binding longer substrates.

CiteULike

Complore

Connotea

Del.icio.us

Digg

Reddit

Technorati

This article has been cited by other articles:

				B. J. Andrews, J. A. Lehman, and J. J. Turchi Kinetic Analysis of the Ku-DNA Binding Activity Reveals a Redox-dependent Alteration in Protein Structure That Stimulates Dissociation of the Ku-DNA Complex J. Biol. Chem., May 12, 2006; 281(19): 13596 - 13603. [Abstract] [Full Text] [PDF]

				H. Jin, J. Sepulveda, and O. R. Burrone Specific recognition of a dsDNA sequence motif by an immunoglobulin VH homodimer Protein Sci., December 1, 2004; 13(12): 3222 - 3229. [Abstract] [Full Text] [PDF]

				D. Arosio, S. Costantini, Y. Kong, and A. Vindigni Fluorescence Anisotropy Studies on the Ku-DNA Interaction: ANION AND CATION EFFECTS J. Biol. Chem., October 8, 2004; 279(41): 42826 - 42835. [Abstract] [Full Text] [PDF]

				J. Bentley, C. P. Diggle, P. Harnden, M. A. Knowles, and A. E. Kiltie DNA double strand break repair in human bladder cancer is error prone and involves microhomology-associated end-joining Nucleic Acids Res., October 5, 2004; 32(17): 5249 - 5259. [Abstract] [Full Text] [PDF]

				S. Cui, R. Klima, A. Ochem, D. Arosio, A. Falaschi, and A. Vindigni Characterization of the DNA-unwinding Activity of Human RECQ1, a Helicase Specifically Stimulated by Human Replication Protein A J. Biol. Chem., January 10, 2003; 278(3): 1424 - 1432. [Abstract] [Full Text] [PDF]

				T. Miyoshi, M. Sadaie, J. Kanoh, and F. Ishikawa Telomeric DNA Ends Are Essential for the Localization of Ku at Telomeres in Fission Yeast J. Biol. Chem., January 10, 2003; 278(3): 1924 - 1931. [Abstract] [Full Text] [PDF]

				D. Matheos, O. Novac, G. B. Price, and M. Zannis-Hadjopoulos Analysis of the DNA replication competence of the xrs-5 mutant cells defective in Ku86 J. Cell Sci., January 1, 2003; 116(1): 111 - 124. [Abstract] [Full Text] [PDF]