Blog
About

7
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: not found

      Organization and ligand binding properties of the tail of Acanthamoeba myosin-IA. Identification of an actin-binding site in the basic (tail homology-1) domain.

      The Journal of Biological Chemistry

      src Homology Domains, Acanthamoeba, chemistry, genetics, Actins, metabolism, Amino Acid Sequence, Animals, Binding Sites, Carrier Proteins, Chromatography, Gel, Circular Dichroism, Cloning, Molecular, DNA, Complementary, Dose-Response Relationship, Drug, Kinetics, Models, Molecular, Molecular Sequence Data, Myosin Heavy Chains, isolation & purification, Myosins, Phylogeny, Protozoan Proteins, Recombinant Proteins, Ultracentrifugation

      Read this article at

      ScienceOpenPubMed
      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          The Acanthamoeba myosin-IA heavy chain gene encodes a 134-kDa protein with a catalytic domain, three potential light chain binding sites, and a tail with separately folded tail homology (TH) -1, -2, and -3 domains. TH-1 is highly resistant to trypsin digestion despite consisting of 15% lysine and arginine. TH-2/3 is resistant to alpha-chymotrypsin digestion. The peptide link between TH-1 and TH-2/3 is cleaved by trypsin, alpha-chymotrypsin, and endo-AspN but not V8 protease. The CD spectra of TH-2/3 indicate predominantly random structure, turns, and beta-strands but no alpha-helix. The hydrodynamic properties of TH-2/3 (Stokes' radius of 3.0 nm, sedimentation coefficient of 1.8 S, and molecular mass of 21.6 kDa) indicate that these domains are as long as the whole myosin-I tail in reconstructions of electron micrographs. Furthermore, separately expressed and purified TH-1 binds with high affinity to TH-2/3. Thus we propose that TH-1 and TH-2/3 are arranged side by side in the myosin-IA tail. Separate TH-1, TH-2, and TH-2/3 each binds muscle actin filaments with high affinity. Salt inhibits TH-2/3 binding to muscle actin but not amoeba actin filaments. TH-1 enhances binding of TH-2/3 to muscle actin filaments at physiological salt concentration, indicating that TH-1 and TH-2/3 cooperate in actin binding. An intrinsic fluorescence assay shows that TH-2/3 also binds with high affinity to the protein Acan125 similar to the SH3 domain of myosin-IC. Phylogenetic analysis of SH3 sequences suggests that myosin-I acquired SH3 domain after the divergence of the genes for myosin-I isoforms.

          Related collections

          Author and article information

          Journal
          10574999

          Comments

          Comment on this article