Morris Burke

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Vertebrate skeletal fast-twitch muscle myosin subfragment 1 is comprised of a heavy polypeptide chain of 95,000 daltons and one alkali light chain of either 21,000 daltons (A1) or 16,500 daltons (A2). In the present study, the heavy chain of subfragment 1 has been separated from the alkali light chain under nondenaturing conditions resembling those in vivo.(More)
Escherichia coli Lon, also known as protease La, is a serine protease that is activated by ATP and other purine or pyrimidine triphosphates. In this study, we examined the catalytic efficiency of peptide cleavage as well as intrinsic and peptide-stimulated nucleotide hydrolysis in the presence of hydrolyzable nucleoside triphosphates ATP, CTP, UTP, and GTP.(More)
The reaction of myosin with three bifunctional sulfhydryl reagents of differing cross-linking span is reported. In the absence of nucleotide only p-N,N'-phenylenedimaleimide with a cross-linking span of 12-14 A can bridge between the two essential sulfhydryls of myosin. The other two reagents, 2,4-dinitro-1,5-difluorobenzene and(More)
The procedure of thermal ion-exchange chromatography has been used to examine the effect of prior tryptic cleavage on the stability of myosin subfragment 1 (SF1). Although it is found that digestion does destabilize the subunit interactions at physiological temperatures, the heavy-chain subunit can be isolated either as an equimolar complex comprised of(More)
Drosophila ninaC gene encodes myosin homologous proteins which are classified as myosin III of the myosin superfamily, yet the physiological and biochemical function of myosin III has not characterized. We report here that myosin III does exhibit protein kinase activity. The kinase homologous domain (MYOIIIPK) of myosin III was expressed in the baculovirus(More)
Myosin has been modified with near stoichiometric amounts of the bifunctional reagent [14C]p-N,N'-phenylenedimaleimide (pPDM) in the presence of MgADP under conditions which abolish its ATPase activity. Subsequent carboxymethylation and CNBr cleavage results in the 14C label being associated with a single polypeptide of Mr approximately 10,000. Amino acid(More)
Methylation of 2-[(2,4-dinitrophenyl)amino]ethyl triphosphate (dNOTP) was found to abolish its ability to support actin sliding in the in vitro motility assay. A comparative study of the interaction of myosin subfragment 1 (S1) and actoS1 with methylated (MdNOTP) and non-methylated dNOTP was undertaken. Both analogues were shown to be substrates for S1(More)
The circular dichroic and fluorescent spectral properties of the myosin head (subfragment I (SFI)) modified by covalently bridging the two essential thiol groups have been examined. CD spectra of SFI with the two thiols linked through reaction with a bifunctional reagent, N, N'- p-phenylenedimaleimide, show enhancement of the 282-nm minimum similar to that(More)