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Insights into copper coordination in the EcoRI-DNA complex by ESR spectroscopy

Ji, Ming and Tan, Likun and Jen-Jacobson, Linda and Saxena, Sunil (2014) Insights into copper coordination in the EcoRI-DNA complex by ESR spectroscopy. Molecular Physics, 112 (24). pp. 3173-3182. ISSN 0026-8976.

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The EcoRI restriction endonuclease requires one divalent metal ion in each of two symmetrical and identical catalytic sites to catalyse double-strand DNA cleavage. Recently, we showed that Cu^(2+) binds outside the catalytic sites to a pair of new sites at H114 in each sub-unit, and inhibits Mg^(2+)-catalysed DNA cleavage. In order to provide more detailed structural information on this new metal ion binding site, we performed W-band (similar to 94GHz) and X-band (similar to 9.5GHz) electron spin resonance spectroscopic measurements on the EcoRI-DNA-(Cu^(2+))_2 complex. Cu^(2+) binding results in two distinct components with different g_(zz) and A_(zz) values. X-band electron spin echo envelope modulation results indicate that both components arise from a Cu^(2+) coordinated to histidine. This observation is further confirmed by the hyperfine sub-level correlation results. W-band electron nuclear double resonance spectra provide evidence for equatorial coordination of water molecules to the Cu^(2+) ions.

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Additional Information:© 2014 Taylor & Francis. Received 8 April 2014, accepted 9 June 2014. This work was supported by a National Science Foundation grant to Sunil Saxena and Linda Jen-Jacobson [grant number MCB 1157712; preparation of purified EcoRI and EcoRI-DNA- CU^(2-) complexes was supported by a National Institutes of Health MERIT grant to Linda Jen-Jacobson [grant number 5R37-GM029207]; the Bruker Elexsys E680 spectrometer was purchased with funds from a National Institute of Health grant [grant number 1Sl0RR028701].
Funding AgencyGrant Number
NSFMCB 1157712
Subject Keywords:W-band ENDOR; ESEEM; metal ion coordination; Cu^(2+) inhibition; restriction endonuclease
Issue or Number:24
Record Number:CaltechAUTHORS:20150112-094230641
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Official Citation:Insights into copper coordination in the EcoRI–DNA complex by ESR spectroscopy Ming Ji, Likun Tan, Linda Jen-Jacobson & Sunil Saxena pages 3173-3182 DOI:10.1080/00268976.2014.934313 Published online: 10 Jul 2014
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:53557
Deposited By: Ruth Sustaita
Deposited On:12 Jan 2015 18:17
Last Modified:03 Oct 2019 07:50

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