Rafael Takashi

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By peptide isolation and analysis, it has been shown that the dansyl fluorophore of dansylcadaverine [N-(5-aminopentyl)-5-(dimethylamino)naphthalene-1-sulfonamide] transfers to Gln-41 of actin from rabbit skeletal muscle when the reaction is catalyzed by guinea pig liver transglutaminase. As a function of time, the degree of labeling asymptotically(More)
We report measurements of the reactivity (degree of labeling, as mole of ligand per mole of protein, at constant exposure time) of the reactive thiol, "SH1", of a subfragment of myosin (S-1), and of Cys-10 of F-actin under various conditions, using N-iodo-[3H]acetyl-N-(1-sulfo-5-naphthyl)ethylenediamine, a fluorescent radioactive iodoacetamide analog. When(More)
A serne residue located in the active site of myosin head (S1) was labelled by 9-anthroylnitrile, an amino group located in the central domain of S1 was labelled by 7-diethylamino-3-(4′-isothio-cyanato-phenyl)-4-methylcoumarin, a cysteine residue located near the C-terminus of S1 was labelled by 5-[2-((iodoacetyl)-amino)ethyl]-amino-naphthalene-1-sulfonic(More)
We have employed the method of radial distance measurements in order to orient the actin monomer in the F-actin filament. This method utilizes fluorescence resonance energy transfer measurements of the distance between two equivalent chemical points located on two different monomers. The interprobe distance obtained this way is used to compute the radial(More)
Myosin subfragment 1 (S-1) was fluorescently labeled at its rapidly reacting thiol ("SH1"). Short exposure to trypsin cuts the S-1 heavy chain into three still-associated fragments (20K, 50K, and 27K) [Balint, M., Wolf, L., Tarcsafalvi, A., Gergely, J., & Sreter, F.A. (1978) Arch. Biochem. Biophys. 190, 793-799] which bind F-actin to the same extent as does(More)
The fast-reacting thiol (SH1) of myosin subfragment-1 (S-1) was covalently and specifically labeled with (iodoacetamido)fluorescein (IAF), while Cys-373 of actin was also covalently and preferentially labeled with N-(iodoacetyl)-N'-(1-sulfo-5-naphthyl)ethylenediamine (1,5-IAEDANS). The method of fluorescence energy transfer was used to examine the spatial(More)
It is proposed that the myosin subfragment 1 moiety of the muscle contractile apparatus is a self-contained "engine" whose operational plan is based on the interactive nature of ATP (or degradation intermediate) binding and actin binding, made possible by an intersite communication system. It is suggested that the spatial information required for examining(More)