title: Localization of two chymotryptic fragments in the structure of renatured bacteriorhodopsin by neutron diffraction.
abstract: The structure of crystalline purple membrane reconstituted from purified bacteriorhodopsin (BR) chymotryptic fragments has been studied by neutron diffraction. In one of the samples studied, the fragment C-2, encompassing the first two predicted transmembrane segments, was prepared from deuterated purple membrane. The diffraction changes when the natural C-2 fragment is substituted by a deuterated one are analysed in terms of a seven-helix model for BR. The assignment of the labelled fragment to one end of the molecule placed new constraints on folding models for the protein.
mesh_terms: D001436:Bacteriorhodopsins / Q000378:metabolism*; D002918:Chymotrypsin; D006217:Halobacterium / Q000378:metabolism; D008958:Models, Molecular; D009501:Neutron Activation Analysis; D010446:Peptide Fragments / Q000378:metabolism; D011487:Protein Conformation; D011489:Protein Denaturation
chemical_list: D010446:Peptide Fragments; D001436:Bacteriorhodopsins; D002918:Chymotrypsin