Influence of the Cardiac Myosin Hinge Region on Contractile Activity

The participation of cardiac myosin hinge in contractility was investigated by in vitro motility and ATPase assays and by measurements of sarcomere shortening. The effect on contractile activity was analyzed using an antibody directed against a 20-amino acid peptide within the hinge region of myosin...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 1991-06, Vol.88 (11), p.4941-4945
Main Authors: Margossian, Sarkis S., Krueger, John W., Sellers, James R., Cuda, Giovanni, Caulfield, James B., Norton, Paul, Slayter, Henry S.
Format: Article
Language:English
Subjects:
Actins
Adenosine triphosphatases
Amino Acid Sequence
Animals
Antibodies
Antigen-Antibody Complex
Biochemistry
Biological and medical sciences
Calcium
cardiac muscle
Cell physiology
contraction
Dogs
Fundamental and applied biological sciences. Psychology
Gizzard, Avian
heart
Heart - physiology
Humans
Microfilaments
Microscopy, Electron
Molecular and cellular biology
Molecular Sequence Data
Muscle contraction
Muscle, Smooth - physiology
Myofibrils
myosin
Myosins - genetics
Myosins - immunology
Myosins - metabolism
Myosins - physiology
Myosins - ultrastructure
Peptides - chemical synthesis
Radioimmunoassay
Rats
role
Sarcomeres
Sarcomeres - physiology
Teeth
Turkeys
Ungulates
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Summary:The participation of cardiac myosin hinge in contractility was investigated by in vitro motility and ATPase assays and by measurements of sarcomere shortening. The effect on contractile activity was analyzed using an antibody directed against a 20-amino acid peptide within the hinge region of myosin. This antibody bound specifically at the hinge at a distance of 55 nm from the S1/S2 junction, was specific to human, dog, and rat cardiac myosins, did not crossreact with gizzard or skeletal myosin, and had no effect on ATPase activity of purified S1 and myofibrils. However, it completely suppressed the movement of actin filaments in in vitro motility assays and reduced active shortening of sarcomeres of skinned cardiac myocytes by half. Suppression of motion by the antihinge antibody may reflect a mechanical constraint imposed by the antibody upon the mobility of the S2 region of myosin. The results suggest that the steps in the mechanochemical energy transduction can be separately influenced through S2.
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.88.11.4941