Download MendeleyStructures of four Ca2+-bound troponin C at 2.0 A resolution: further insights into the Ca2+-switch in the calmodulin superfamily.
Houdusse, A., Love, M.L., Dominguez, R., Grabarek, Z., Cohen, C.(1997) Structure 5: 1695-1711
- PubMed: 9438870
- DOI: https://doi.org/10.1016/s0969-2126(97)00315-8
- Primary Citation of Related Structures:
1TN4, 2TN4 - PubMed Abstract:
In contrast to Ca2+4-bound calmodulin (CaM), which has evolved to bind to many target sequences and thus regulate the function of a variety of enzymes, troponin C (TnC) is a bistable switch which controls contraction in striated muscles. The specific target of TnC is troponin I (TnI), the inhibitory subunit of the troponin complex on the thin filaments of muscle. To date, only the crystal structure of Ca2+2-bound TnC (i.e. in the 'off' state) had been determined, which together with the structure of Ca2+4-bound CaM formed the basis for the so-called 'HMJ' model of the conformational changes in TnC upon Ca2+ binding. NMR spectroscopic studies of Ca2+4-bound TnC (i.e. in the 'on' state) have recently been carried out, but the detailed conformational changes that take place upon switching from the off to the on state have not yet been described.
Organizational Affiliation:
Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02254-9110, USA.
