The effect of troponin C removal on the Ca2+-sensitive binding of Mg2+ AMPPNP to myofibrils.
نویسنده
چکیده
It was previously shown that when rabbit skeletal myofibrils are titrated with Mg2+ AMPPNP under conditions that result in the dissociation of cross-bridges from the thin filaments (i.e. 50% ethylene glycol, 0 degrees C), Ca2+-sensitive, biphasic binding is observed. These titrations have been repeated using myofibrils from which the troponin C has been selectively removed. The disappearance of both Ca2+ sensitivity and biphasic binding is taken as evidence that the Ca2+ sensitivity is due to Ca2+ binding to troponin C and the biphasic binding of Mg2+ AMPPNP observed in intact myofibrils is not due to packing constraints or steric hindrance.
منابع مشابه
Changes in myofibrillar activation and troponin C Ca2+ binding associated with troponin T isoform switching in developing rabbit heart.
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Troponin C (TnC)-depleted myofibrils from rabbit skeletal muscle were prepared by consecutive washes of whole myofibrils with EDTA in solutions of low ionic strength, a method which has recently been described for the preparation of TnC (Cox, J. A., Compte, M., and Stein, E. A. (1981) Biochem. J. 195,205-211). Myofibrils treated in this manner exhibit a calcium independent loss of myofibrillar ...
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عنوان ژورنال:
- FEBS letters
دوره 232 2 شماره
صفحات -
تاریخ انتشار 1988