title: Effect of nucleotide on interaction of the 567-578 segment of myosin heavy chain with actin.
abstract: To probe the effect of nucleotide on the formation of ionic contacts between actin and the 567-578 residue loop of the heavy chain of rabbit skeletal muscle myosin subfragment 1 (S1), the complexes between F-actin and proteolytic derivatives of S1 were submitted to chemical cross-linking with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide. We have shown that in the absence of nucleotide both 45 kDa and 5 kDa tryptic derivatives of the central 50 kDa heavy chain fragment of S1 can be cross-linked to actin, whereas in the presence of MgADP.AlF4, only the 5 kDa fragment is involved in cross-linking reaction. By the identification of the N-terminal sequence of the 5-kDa fragment, we have found that trypsin splits the 50 kDa heavy chain fragment between Lys-572 and Gly-573, the residues located within the 567-578 loop. Using S1 preparations cleaved with elastase, we could show that the residue of 567-578 loop that can be cross-linked to actin in the presence of MgADP.AlF4 is Lys-574. The observed nucleotide-dependent changes of the actin-subfragment 1 interface indicate that the 567-578 residue loop of skeletal muscle myosin participates in the communication between the nucleotide and actin binding sites.
authors.affiliation: NIMH, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Brian M
authors.initials: BM
authors.lastname: Martin
authors.forename: Emilia
authors.initials: E
authors.lastname: Karczewska
authors.forename: Barbara
authors.initials: B
authors.lastname: Pliszka
mesh_terms: D000199:Actins / Q000737:chemistry*; D000244:Adenosine Diphosphate / Q000737:chemistry*; D000595:Amino Acid Sequence; D000818:Animals; D003432:Cross-Linking Reagents / Q000737:chemistry; D005022:Ethyldimethylaminopropyl Carbodiimide / Q000737:chemistry; D018995:Myosin Heavy Chains / Q000737:chemistry*; D015879:Myosin Subfragments / Q000737:chemistry*; D010446:Peptide Fragments / Q000737:chemistry; D025941:Protein Interaction Mapping; D011817:Rabbits; D015719:Single-Strand Specific DNA and RNA Endonucleases / Q000737:chemistry
chemical_list: D000199:Actins; D003432:Cross-Linking Reagents; D015879:Myosin Subfragments; D010446:Peptide Fragments; C033025:actin subfragments; D000244:Adenosine Diphosphate; D015719:Single-Strand Specific DNA and RNA Endonucleases; D018995:Myosin Heavy Chains; D005022:Ethyldimethylaminopropyl Carbodiimide