Observation of inter-subunit nuclear Overhauser effects in a dimeric protein: Application to the Arc repressor

Abstract

For the structure determination of symmetric protein dimers it is necessary to distinguish between intra- and inter-subunit NOEs. A method is presented to measure selectively the inter-subunit NOEs using uniform 15N and 13C isotope labelling. This is accomplished by doubly filtered 2D NOE experiments on mixtures of native protein with isotope-labeled protein. The method has been applied to the Arc represser and allows the characterization of virtually all proton-proton NOEs in terms of their intra- or inter-subunit nature.