Distance determination between low-spin ferric haem and nitroxide spin label using DEER: the neuroglobin case

Article Article scientifique Article Distance determination between low-spin ferric haem and nitroxide spin label using DEER: the neuroglobin case eng 2013-07-08 2013-07-08 author Ezhevskaya M. author Bordignon Enrica 0000-0003-2450-5161 973830 Département de chimie physique (CHIFI) author Polyhach Y. author Moens L. author Dewilde Sebastian 544277 author Jeschke G. author Van Doorslaer Sabine 2855-2864 10.1080/00268976.2013.813592 0026-8976 http://www.tandfonline.com/doi/abs/10.1080/00268976.2013.813592 This work demonstrates for the first time the feasibility of using double electron–electron resonance (DEER) to determine the inter-spin distance between nitroxide spin labels and low-spin (<i>S</i> = 1/2) ferric haem centres. For these means, two human neuroglobin variants were spin labelled leading to singly labelled haem proteins with the nitroxide label on one of the natural Cys residues (Cys55 or Cys120). Room-temperature electron paramagnetic resonance was used to characterise the mobility of the nitroxide labels and X- and Q-band DEER experiments were performed to detect nitroxide–haem distances. Effects of residual nuclear modulations in the DEER traces were carefully evaluated. The DEER-derived distances were compared with theoretical predictions from an X-ray diffraction structure of human neuroglobin using a rotamer library approach as well as with distance information obtained from electron relaxation measurements. The structural biological implications of the spin-labelled side chains’ dynamics and of the obtained distances are also discussed. EPR Distance mesurements Neuroglobin true Molecular physics 111 18-19 0906ab5d-ecc4-4fba-a8da-11ce2508f33b Article (Published version) Restricted BORDIGNON34(1).pdf 1292996 application/pdf d374ece3f5d07b452c4d63eaa582fb31c32c83f59ecacd2a27c6b9e09fcd3f6f restrictedAccess

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Distance determination between low-spin ferric haem and nitroxide spin label using DEER: the neuroglobin case	Molecular physics			2013	81	0

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Dewilde, Sebastian