title: Dimerization of native myosin LC2(RLC)-free subfragment 1 from adult rabbit skeletal muscle.
abstract: We reinvestigated whether the native myosin LC2-free-subfragment 1 (S1) dimer exists by using viscometry, capillary electrophoresis, and laser light scattering. We found that the intrinsic viscosity of the monomer is [eta]m = 6.7 cm3/g and its translation diffusion coefficient is (c = 0) = 4.43 x 10(-)7 cm2/s. For the dimer, [eta]d = 19.8 cm3/g and (c = 0) = 2.54 x 10(-)7 cm2/s. Using the Svedberg equation and introducing the values of the sedimentation coefficients (5.05 S for the monomer and 6.05 S for the dimer), we find the following molecular weights: Mr,m = 108 000 Da and Mr,d = 213 000 Da, which agree well with previous determinations. Capillary electrophoresis successfully separated S1(A1) and S1(A2), in a monomer buffer, and S1(A1) and S1(A2) and a heterodimer S1(A1)-S1(A2), in a dimer buffer. An interesting feature of the monomer-dimer equilibrium is the presence of temperature transitions, whose positions and widths depend upon the buffer conditions. At low temperatures, a pure dimer was observed, whereas at high temperatures only the monomer was present. The dimerization site on both myosin and S1 is extremely labile.
authors.affiliation: Laboratoire de Biologie, Ecole Centrale de Paris, Châtenay-Malabry, France.
authors.forename: J E
authors.initials: JE
authors.lastname: Morel
authors.forename: K
authors.initials: K
authors.lastname: Taouil
authors.forename: N
authors.initials: N
authors.lastname: D'hahan
authors.forename: A
authors.initials: A
authors.lastname: Aguilar
authors.forename: Z
authors.initials: Z
authors.lastname: Merah
authors.forename: J P
authors.initials: JP
authors.lastname: Dalbiez
authors.forename: P
authors.initials: P
authors.lastname: Bayol
authors.forename: N
authors.initials: N
authors.lastname: Guillo
authors.forename: L
authors.initials: L
authors.lastname: Patard
authors.forename: V
authors.initials: V
authors.lastname: Cabane
authors.forename: M
authors.initials: M
authors.lastname: Ferrari
authors.forename: G
authors.initials: G
authors.lastname: Figuera Picazo
authors.forename: H
authors.initials: H
authors.lastname: Dam Hieu
authors.forename: M
authors.initials: M
authors.lastname: Francin
mesh_terms: D000266:Adenylyl Imidodiphosphate / Q000378:metabolism; D000818:Animals; D002021:Buffers; D017301:Ca(2+) Mg(2+)-ATPase / Q000378:metabolism; D019281:Dimerization; D019075:Electrophoresis, Capillary; D008956:Models, Chemical; D018482:Muscle, Skeletal / Q000737:chemistry / Q000378:metabolism*; D018994:Myosin Light Chains / Q000737:chemistry / Q000378:metabolism*; D015879:Myosin Subfragments / Q000737:chemistry / Q000378:metabolism*; D011817:Rabbits; D014783:Viscosity
chemical_list: D002021:Buffers; D018994:Myosin Light Chains; D015879:Myosin Subfragments; D000266:Adenylyl Imidodiphosphate; D017301:Ca(2+) Mg(2+)-ATPase