title: Conformational changes of S-1 related to its dissociation from actin.
abstract: The peptide pattern obtained after proteolysis of S-1 with trypsin was different in the absence or presence of anions. The affinity of tryptic and undigested S-1 for anions (CN-, SCN- or HCO3-) was different, as reflected by the altered values of Ki or Ka obtained from ATPase activity measurements. Anions CN-, SCN-, HCO3-, or PPi induced dissociation of actomyosin when added to acto-S-1 or acto-heavy-meromyosin. Among nucleoside di- and triphosphates, only triphosphates were effective with regard to the dissociation. The results suggest the existence of a regulatory site of cationic nature on S-1, which might be involved in the dissociation of actin from myosin.
authors.affiliation: Departamento de Bioquímica, Universidad de Navarra, Pamplona, Spain.
authors.forename: S
authors.initials: S
authors.lastname: Sanz
authors.forename: M J
authors.initials: MJ
authors.lastname: Gil
authors.forename: M J
authors.initials: MJ
authors.lastname: López-Zabalza
authors.forename: N
authors.initials: N
authors.lastname: López-Moratalla
authors.forename: E
authors.initials: E
authors.lastname: Santiago
mesh_terms: D000199:Actins / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000495:Allosteric Site; D000818:Animals; D000838:Anions / Q000494:pharmacology*; D001639:Bicarbonates / Q000494:pharmacology; D001665:Binding Sites; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D002645:Chickens; D003486:Cyanides / Q000494:pharmacology; D004789:Enzyme Activation; D015879:Myosin Subfragments / Q000378:metabolism*; D009218:Myosins / Q000378:metabolism; D010449:Peptide Mapping; D011485:Protein Binding; D011487:Protein Conformation / Q000187:drug effects; D013861:Thiocyanates / Q000494:pharmacology; D014357:Trypsin
chemical_list: D000199:Actins; D000838:Anions; D001639:Bicarbonates; D003486:Cyanides; D015879:Myosin Subfragments; D013861:Thiocyanates; D000255:Adenosine Triphosphate; D014357:Trypsin; D009218:Myosins; D000252:Calcium-Transporting ATPases