OBSERVATION OF INTER-SUBUNIT NUCLEAR OVERHAUSER EFFECTS IN A DIMERIC PROTEIN - APPLICATION TO THE ARC REPRESSOR

For the structure determination of symmetric protein dimers it is nece ssary to distinguish between intra- and inter-subunit NOEs. A method i s presented to measure selectively the inter-subunit NOEs using unifor m N-15 and C-13 isotope labelling. This is accomplished by doubly filt ered 2D NOE experiments on mixtures of native protein with isotope-lab eled protein. The method has been applied to the Arc repressor and all ows the characterization of virtually all proton-proton NOEs in terms of their intra- or inter-subunit nature.