The enzymic properties of N-ethylmaleimide modified myosin

Sekine, Toshimori; Kielley, W. Wayne

doi:10.1016/0926-6569(64)90049-5

Cited by 102 publications

(125 citation statements)

References 27 publications

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“…Chemical and structural studies of myosin have indicated that there must be a significant structural rearrangement associated with the reactive sulffihydryl groups during the contractile cycle (38)(39)(40)(41). In the structure of chicken skeletal myosin Si, these two residues are separated by an a-helix where their side chains point in opposite directions (23), yet they can be cross-linked in the presence of nucleotide (42)(43)(44) and chemical modification of the cysteines changes the kinetic properties of myosin (45,46). It has been suggested that domain movements around the reactive sulfhydryl pocket allows the molecule to bend during the contractile cycle without inducing major structural rearrangements within the domains themselves (47).…”

Section: Resultsmentioning

confidence: 99%

Structural interpretation of the mutations in the beta-cardiac myosin that have been implicated in familial hypertrophic cardiomyopathy.

Rayment

Holden

Sellers

et al. 1995

Proc. Natl. Acad. Sci. U.S.A.

211

142

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In 10-30% of hypertrophic cardiomyopathy kindreds, the disease is caused by >29 missense mutations in the cardiac f8-myosin heavy chain (AYIH7) gene. The amino acid sequence similarity between chicken skeletal muscle and human a-cardiac myosin and the three-dimensional structure of the chicken skeletal muscle myosin head have provided the opportunity to examine the structural consequences of these naturally occurring mutations in human ,8-cardiac myosin. This study demonstrates that the mutations are related to distinct structural and functional domains. Twenty-four are clustered around four specific locations in the myosin head that are (i) associated with the actin binding interface, (ii) around the nucleotide binding site, (iii) adjacent to the region that connects the two reactive cysteine residues, and (iv) in close proximity to the interface of the heavy chain with the essential light chain. The remaining five mutations are in the myosin rod. The locations of these mutations provide insight into the way they impair the functioning of this molecular motor and also into the mechanism of energy transduction.

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Section: Resultsmentioning

confidence: 99%

Structural interpretation of the mutations in the beta-cardiac myosin that have been implicated in familial hypertrophic cardiomyopathy.

Rayment

Holden

Sellers

et al. 1995

Proc. Natl. Acad. Sci. U.S.A.

211

142

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“…The equal inhibition of Ca2+ ATPase and K + -EDTA ATPase activities shows that the pressure effect is not due to the selective destruction of one of the two reactive sulphydryl groups located at or near the active site of myosin (Sekine and Kielley 1964). If, as reported by Reisler et al (1974), the SH i group is more exposed than the SH z group in the absence of nucleotide, a selective destruction might be expected if pressure was affecting this area of the molecule.…”

Section: Atpase Measurementsmentioning

confidence: 98%

Some Effects of Pressure Treatment on Actomyosin Systems

O'shea¹,

Horgan²,

JMacfarlane³

1976

Aust. Jnl. Of Bio. Sci.

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Natural actomyosin, actin and myosin, have been pressurized at up to 150 MN/m2 for 1 h at O°C and examined 3-5 h later.Pressurization of myosin resulted in the formation of aggregates with a molecular weight approximately that expected for a dimer, whereas with F-actin depolymerization occurred. With actomyosin, a gel to sol transition was promoted. Viscosity and light-scattering measurements indicated that pressurization results in a large measure of disaggregation of actomyosin in solution.Pressurization of actomyosin resulted in a greater decrease in the calcium-sensitive, than in the calcium-independent, Mg2+ ATPase activity. The Ca 2 + and K+-EDTA ATPase activities of myosin were inhibited to about the same extent.

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“…Modification of SH-1 results in the activation of Ca2+-ATPase activity and the abolition of K+-ATPase activity. Reaction of the second thiol takes place only in the presence of nucleotide and leads to a loss of Ca2+-ATPase activity also (1,2). By blocking SH-1 reversibly with fluorodinitrobenzene, Reisler et al (3) showed that myosin exhibits a smaller increase in Ca2+-ATPase activity when SH-2, instead of SH-1, is modified with N-ethylmaleimide.…”

mentioning

confidence: 99%

“…There are two reactive thiols, SH-1 and SH-2, in myosin subfragment 1 (Si). Modification of SH-1 results in the activation of Ca2+-ATPase activity and the abolition of K+-ATPase activity.…”

mentioning

confidence: 99%

Both the 25-kDa and 50-kDa domains in myosin subfragment 1 are close to the reactive thiols.

Lu¹,

Moo²,

Wong³

1986

Proc. Natl. Acad. Sci. U.S.A.

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Both the 25-kDa and 50-kDa domains in myosin subfragment 1 are close to the reactive thiols (benzophenone-4- Communicated by Russell F. Doolittle, May 23, 1986 ABSTRACT The thiol-specific photoactivatable reagent benzophenone-4-iodoacetamide can be incorporated into myosin subfragment 1 (Si), accompanied by an increase of Ca2+-ATPase and the loss of K+-ATPase activities, a characteristic property of S1 when reactive sulfhydryl 1 (SH-1) Is modified. After trypsin cleavage, 25-kDa, 50-kDa, and 20-kDa fragments were found upon NaDodSO4/polyacrylamide gel electrophoresis of the unphotolyzed sample, whereas only the 50-kDa fragment and a 45-kDa fragment appeared In the photolyzed sample, indicating that the NH2-terminal 25-kDa fragment was crosslinked to the COOH-terminal 20-kDa fragment via SH-1. When photolysis 'was carried out in the presence of Mg2+ and ATP or Mg2e and adenosine 5-[,B, imidoltriphosphate (AdoPP[NHJP), a 70-kDa band, attribu-

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The enzymic properties of N-ethylmaleimide modified myosin

Cited by 102 publications

References 27 publications

Structural interpretation of the mutations in the beta-cardiac myosin that have been implicated in familial hypertrophic cardiomyopathy.

Structural interpretation of the mutations in the beta-cardiac myosin that have been implicated in familial hypertrophic cardiomyopathy.

Some Effects of Pressure Treatment on Actomyosin Systems

Both the 25-kDa and 50-kDa domains in myosin subfragment 1 are close to the reactive thiols.

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