title: Interaction of myosin LYS-553 with the C-terminus and DNase I-binding loop of actin examined by fluorescence resonance energy transfer.
abstract: Fluorescence resonance energy transfer (FRET) experiments were carried out in the absence of nucleotide (rigor) or in the presence of MgADP between fluorescent donor probes (IAEDANS (5((((2-iodoacetyl)amino)ethyl)amino)-naphthalene-1-sulfonic acid) at Cys-374 or DANSYL (5-dimethylamino naphthalene-1-(N-(5-aminopentyl))sulfonamide) at Gln-41 of actin and acceptor molecules (FHS (6-[fluorescein-5(and 6)-carboxamido] hexanoic acid succinimidyl ester) at Lys-553 of skeletal muscle myosin subfragment 1. The critical Förster distance (R(0)) was determined to be 44 and 38 A for the IAEDANS-FHS and DANSYL-FHS donor-acceptor pairs, respectively. The efficiency of energy transfer between the acceptor molecules at Lys-553 of myosin and donor probes at Cys-374 or Gln-41 of actin was calculated to be 0.78 +/- 0.01 or 0.94 +/- 0.01, respectively, corresponding to distances of 35.6 +/- 0.4 A and 24.0 +/- 1.6 A, respectively. MgADP had no significant effect on the distances observed in rigor. Thus, rearrangements in the acto-myosin interface are likely to occur elsewhere than in the lower 50-kDa subdomain of myosin as its affinity for actin is weakened by MgADP binding.
authors.affiliation: Department of Molecular Physiology and Biophysics, University of Vermont College of Medicine, Burlington, Vermont 05405-0068, USA.
authors.forename: C M
authors.initials: CM
authors.lastname: Yengo
authors.forename: L R
authors.initials: LR
authors.lastname: Chrin
authors.forename: C L
authors.initials: CL
authors.lastname: Berger
mesh_terms: D000199:Actins / Q000737:chemistry* / Q000378:metabolism; D000244:Adenosine Diphosphate / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D001665:Binding Sites; D003619:Dansyl Compounds; D003850:Deoxyribonuclease I / Q000378:metabolism; D005456:Fluorescent Dyes; D066298:In Vitro Techniques; D008239:Lysine / Q000737:chemistry; D046911:Macromolecular Substances; D008958:Models, Molecular; D009218:Myosins / Q000737:chemistry* / Q000378:metabolism; D009282:Naphthalenesulfonates; D011817:Rabbits; D013050:Spectrometry, Fluorescence
chemical_list: D000199:Actins; D003619:Dansyl Compounds; D005456:Fluorescent Dyes; D046911:Macromolecular Substances; D009282:Naphthalenesulfonates; D000244:Adenosine Diphosphate; C006421:1,5-I-AEDANS; D003850:Deoxyribonuclease I; D009218:Myosins; D008239:Lysine