title: The conformation of the C-terminal region of actin: a site-specific photocrosslinking study using benzophenone-4-maleimide.
abstract: The site-specific photocrosslinker, benzophenone-4-maleimide, was used to label G-actin specifically at Cys-374, the penultimate residue from the C terminus. The resultant BP-G-actin was polymerized to form BP-F-actin, and both forms of actin were irradiated to activate the benzophenone moiety. We found that for BP-F-actin both intersubunit and intrasubunit photocrosslinks were formed. For BP-G-actin only a small amount of an internally photocrosslinked species was formed. These findings suggest that in the F-actin polymer, the C-terminal peptide is localized in a region between neighboring subunits. In contrast, in the G-actin monomer, the C-terminal peptide is relatively distant from the surface of the molecule.
mesh_terms: D000199:Actins / Q000032:analysis* / Q000528:radiation effects; D000818:Animals; D001577:Benzophenones; D003432:Cross-Linking Reagents; D004591:Electrophoresis, Polyacrylamide Gel; D007700:Kinetics; D008301:Maleimides; D010777:Photochemistry; D011108:Polymers / Q000032:analysis; D011487:Protein Conformation; D011817:Rabbits; D013053:Spectrophotometry
chemical_list: D000199:Actins; D001577:Benzophenones; D003432:Cross-Linking Reagents; D008301:Maleimides; D011108:Polymers; C046109:benzophenone-4-maleimide