title: Non-polymerizing long-pitch actin dimers that interact with myosin.
abstract: The production of a soluble actomyosin complex would be a significant step toward elucidating molecular interactions responsible for biological movement. We took a systematic approach to producing soluble long-pitch actin dimers that are polymerization-deficient yet retain biological protein-protein interactions, including myosin binding. Actin mutant proteins and chemical crosslinking were combined with different polymerization inhibition strategies, including ADP-ribosylation, or the use of a polymerization-deficient actin mutant protein. While all of the long-pitch actin dimers retained interactions reflective of F-actin activity, each displayed different interactions with myosin. Myosin did not interact productively with long-pitch actin dimers capped with DNase-I, and led to filament formation of unmodified long-pitch actin dimers or dimers possessing a polymerization-deficient actin subunit. However, ADP-ribosylated long-pitch actin dimers interacted with myosin, giving this dimer great potential for producing a soluble actomyosin complex, which could greatly improve our understanding of the molecular basis of movement in cells, tissues, and organisms.
authors.affiliation: Biophysics Interdepartmental Group and Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ont., Canada N1G 2W1.
authors.forename: Scott S
authors.initials: SS
authors.lastname: Morrison
authors.forename: Ana
authors.initials: A
authors.lastname: Loncar
authors.forename: John F
authors.initials: JF
authors.lastname: Dawson
mesh_terms: D000199:Actins / Q000737:chemistry*; D000205:Actomyosin / Q000737:chemistry; D000818:Animals; D001665:Binding Sites; D002417:Cattle; D002645:Chickens; D003432:Cross-Linking Reagents; D019281:Dimerization; D066298:In Vitro Techniques; D008958:Models, Molecular; D050505:Mutant Proteins / Q000737:chemistry; D015879:Myosin Subfragments / Q000737:chemistry; D009218:Myosins / Q000737:chemistry*; D054730:Protein Interaction Domains and Motifs
chemical_list: D000199:Actins; D003432:Cross-Linking Reagents; D050505:Mutant Proteins; D015879:Myosin Subfragments; D000205:Actomyosin; D009218:Myosins