Distance determination between low-spin ferric haem and nitroxide spin label using DEER

Ondertitel:the neuroglobin case

This work demonstrates for the first time the feasibility of using double electronelectron resonance (DEER) to determine the inter-spin distance between nitroxide spin labels and low-spin (S = 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 nitroxidehaem 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.

Jaar van publicatie:2013

BOF-keylabel:ja

CSS-citation score:1

Auteurs:International

Authors from:Higher Education

Toegankelijkheid:Closed