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NMR analysis of cardiac troponin C‐troponin I complexes: effects of phosphorylation
Author(s) -
Finley Natosha,
Abbott M.Bret,
Abusamhadneh Ekram,
Gaponenko Vadim,
Dong Wen-ji,
Gasmi-Seabrook G.,
Howarth Jack W.,
Rance Mark,
Solaro R.John,
Cheung Herbert C.,
Rosevear Paul R.
Publication year - 1999
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(99)00693-6
Subject(s) - troponin i , troponin , troponin c , troponin complex , troponin t , phosphorylation , chemistry , biochemistry , cardiology , medicine , myocardial infarction
Phosphorylation of the cardiac specific amino‐terminus of troponin I has been demonstrated to reduce the Ca 2+ affinity of the cardiac troponin C regulatory site. Recombinant N‐terminal cardiac troponin I proteins, cardiac troponin I(33–80), cardiac troponin I(1–80), cardiac troponin I(1–80)DD and cardiac troponin I(1–80)pp, phosphorylated by protein kinase A, were used to form stable binary complexes with recombinant cardiac troponin C. Cardiac troponin I(1–80)DD, having phosphorylated Ser residues mutated to Asp, provided a stable mimetic of the phosphorylated state. In all complexes, the N‐terminal domain of cardiac troponin I primarily makes contact with the C‐terminal domain of cardiac troponin C. The non‐phosphorylated cardiac specific amino‐terminus, cardiac troponin I(1–80), was found to make additional interactions with the N‐terminal domain of cardiac troponin C.