title: Purification from Dictyostelium discoideum of a low-molecular-weight myosin that resembles myosin I from Acanthamoeba castellanii.
abstract: A low-molecular-weight myosin has been purified 1500-fold from extracts of Dictyostelium discoideum, based on the increase in K+,EDTA-ATPase specific activity. The purified enzyme resembles the single-headed, low-molecular-weight myosins IA and IB from Acanthamoeba castellanii, and differs from the conventional two-headed, high-molecular-weight myosin previously isolated from Dictyostelium, in several ways. It has higher K+,EDTA-ATPase activity than Ca2+-ATPase activity; it has a native molecular mass of about 150,000 and a single heavy chain of about 117,000; the 117,000-dalton heavy chain is phosphorylated by Acanthamoeba myosin I heavy chain kinase; phosphorylation of its heavy chain enhances its actin-activated Mg2+-ATPase activity; and the 117,000-dalton heavy chain reacts with antibodies raised against the heavy chain of Acanthamoeba myosin IA. None of these properties is shared by the low-molecular-weight active fragment that can be produced by chymotryptic digestion of conventional Dictyostelium myosin. We conclude that Dictyostelium contains an enzyme of the myosin I type previously isolated only from Acanthamoeba.
authors.forename: G P
authors.initials: GP
authors.lastname: Côté
authors.forename: J P
authors.initials: JP
authors.lastname: Albanesi
authors.forename: T
authors.initials: T
authors.lastname: Ueno
authors.forename: J A
authors.initials: JA
authors.lastname: Hammer
authors.forename: E D
authors.initials: ED
authors.lastname: Korn
mesh_terms: D000199:Actins / Q000494:pharmacology; D000251:Adenosine Triphosphatases / Q000378:metabolism; D000656:Amoeba / Q000201:enzymology*; D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D027682:Cation Transport Proteins; D003429:Cross Reactions; D004023:Dictyostelium / Q000201:enzymology*; D004492:Edetic Acid / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation; D007527:Isoenzymes / Q000302:isolation & purification*; D008970:Molecular Weight; D009218:Myosins / Q000302:isolation & purification*; D010766:Phosphorylation
chemical_list: D000199:Actins; D027682:Cation Transport Proteins; D007527:Isoenzymes; D004492:Edetic Acid; D000251:Adenosine Triphosphatases; D017301:Ca(2+) Mg(2+)-ATPase; C022761:potassium transporting ATPase; D009218:Myosins; D000252:Calcium-Transporting ATPases