title: Nucleotide-induced change of the interaction between the 20- and 26-kilodalton heavy-chain segments of myosin adenosinetriphosphatase revealed by chemical cross-linking via the reactive thiol SH2.
abstract: When myosin subfragment 1 (S-1) reacts with the bifunctional reagents with cross-linking spans of 3-4.5 A, p-nitrophenyl iodoacetate and p-nitrophenyl bromoacetate, the 20-kilodalton (20-kDa) segment of the heavy chain is cross-linked to the 26-kDa segment via the reactive thiol SH2. The well-defined reactive lysyl residue Lys-83 of the 26-kDa segment was not involved in the cross-linking. The cross-linking was completely abolished by nucleotides. Taking into account the recent report that SH2 is cross-linked to a thiol of the 50-kDa segment of S-1 using a reagent with a cross-linking span of 2 A [Chaussepied, P., Mornet, D., & Kassab, R. (1986) Proc. Natl. Acad. Sci. U.S.A. 83, 2037-2041], present results suggest that SH2 of S-1 lies close to both the 26- and 50-kDa segments of the heavy chain. The data also encourage us to confirm our previous suggestion that the ATPase site of S-1 residues at or near the region where all three segments of 26, 50, and 20 kDa are contiguous [Hiratsuka, T. (1984) J. Biochem. (Tokyo) 96, 269-272; Hiratsuka, T. (1985) J. Biochem. (Tokyo) 97, 71-78].
mesh_terms: D000085:Acetates / Q000494:pharmacology*; D000244:Adenosine Diphosphate / Q000494:pharmacology*; D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D003432:Cross-Linking Reagents / Q000494:pharmacology*; D005033:Ethylmaleimide / Q000494:pharmacology*; D007461:Iodoacetates / Q000494:pharmacology*; D008239:Lysine; D008274:Magnesium / Q000494:pharmacology; D008970:Molecular Weight; D009132:Muscles / Q000201:enzymology; D015879:Myosin Subfragments; D009218:Myosins / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism*; D011487:Protein Conformation; D011817:Rabbits; D013438:Sulfhydryl Compounds / Q000378:metabolism
chemical_list: D000085:Acetates; D003432:Cross-Linking Reagents; D007461:Iodoacetates; D015879:Myosin Subfragments; D010446:Peptide Fragments; D013438:Sulfhydryl Compounds; C053422:4-nitrophenyl bromoacetate; C053421:4-nitrophenyl iodoacetate; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; D009218:Myosins; D008274:Magnesium; D008239:Lysine; D005033:Ethylmaleimide