title: Acetylation at the N-terminus of actin strengthens weak interaction between actin and myosin.
abstract: The N-terminus of all actins so far studied is acetylated. Although the pathways of acetylation have been well studied, its functional importance has been unclear. A negative charge cluster in the actin N-terminal region is shown to be important for the function of actomyosin. Acetylation at the N-terminus removes a positive charge and increases the amount of net negative charges in the N-terminal region. This may augment the role of the negative charge cluster. To examine this possibility, actin with a nonacetylated N-terminus (nonacetylated actin) was produced. The nonacetylated actin polymerized and depolymerized normally. In actin-activated heavy meromyosin ATPase assays, the nonacetylated actin showed higher K(app) without significantly changing V(max), compared with those of wild-type actin. This is in contrast to the effect of the N-terminal negative charge cluster, which increases V(max) without changing K(app). These results indicate that the acetylation at the N-terminus of actin strengthens weak actomyosin interaction.
authors.affiliation: Department of Physics, School of Science, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo, 113-0033, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Abe
authors.forename: K
authors.initials: K
authors.lastname: Saeki
authors.forename: T
authors.initials: T
authors.lastname: Yasunaga
authors.forename: T
authors.initials: T
authors.lastname: Wakabayashi
mesh_terms: D000107:Acetylation; D000199:Actins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D000251:Adenosine Triphosphatases / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D004023:Dictyostelium / Q000235:genetics; D004563:Electrochemistry; D066298:In Vitro Techniques; D007700:Kinetics; D008854:Microscopy, Electron; D015879:Myosin Subfragments / Q000378:metabolism; D009218:Myosins / Q000378:metabolism*; D011485:Protein Binding; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D000199:Actins; D015879:Myosin Subfragments; D011994:Recombinant Proteins; D000251:Adenosine Triphosphatases; D009218:Myosins