Ca(2+)-induced secondary structural changes of troponin I.
نویسندگان
چکیده
منابع مشابه
Structural consequences of cardiac troponin I phosphorylation.
beta-Adrenergic stimulation of the heart results in bisphosphorylation of the N-terminal extension of cardiac troponin I (TnI). Bisphosphorylation of TnI reduces the affinity of the regulatory site on troponin C (TnC) for Ca(2+) by increasing the rate of Ca(2+) dissociation. What remains unclear is how the phosphorylation signal is transmitted from one subunit of troponin to another. We have pr...
متن کاملCa(2+)-regulated structural changes in troponin.
Troponin senses Ca2+ to regulate contraction in striated muscle. Structures of skeletal muscle troponin composed of TnC (the sensor), TnI (the regulator), and TnT (the link to the muscle thin filament) have been determined. The structure of troponin in the Ca(2+)-activated state features a nearly twofold symmetrical assembly of TnI and TnT subunits penetrated asymmetrically by the dumbbell-shap...
متن کاملCa2+-induced conformational transition in the inhibitory and regulatory regions of cardiac troponin I.
Cardiac muscle activation is initiated by the binding of Ca(2+) to the single N-domain regulatory site of cardiac muscle troponin C (cTnC). Ca(2+) binding causes structural changes between cTnC and two critical regions of cardiac muscle troponin I (cTnI): the regulatory region (cTnI-R, residues 150-165) and the inhibitory region (cTnI-I, residues130-149). These changes are associated with a dec...
متن کاملThe effect of troponin I phosphorylation on the Ca2+-binding properties of the Ca2+-regulatory site of bovine cardiac troponin.
The effect troponin I phosphorylation has on the Ca2+-binding properties of troponin C (TnC) in the whole troponin complex reconstituted from cardiac troponin I (TnI), troponin T, and TnC has been measured. To selectively follow Ca2+ binding at the Ca2+-specific sites of TnC, this subunit was labeled with the fluorescent probe 2-(4’-iodo-acetamidoanilino)naphthalene-6sulfonic acid before recons...
متن کاملStructural changes induced in Ca2+-regulated myosin filaments by Ca2+ and ATP
We have used electron microscopy and proteolytic susceptibility to study the structural basis of myosin-linked regulation in synthetic filaments of scallop striated muscle myosin. Using papain as a probe of the structure of the head-rod junction, we find that this region of myosin is approximately five times more susceptible to proteolytic attack under activating (ATP/high Ca2+) or rigor (no AT...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Seibutsu Butsuri
سال: 2001
ISSN: 0582-4052,1347-4219
DOI: 10.2142/biophys.41.s61_4