2JNF

Solution structure of fly troponin C, isoform F1

Summary for 2JNF

• Entry DOI: 10.2210/pdb2jnf/pdb
• NMR Information: BMRB: 6081
• Descriptor: Troponin C (1 entity in total)
• Functional Keywords: stretch activated muscle contraction, troponin c, ef-hand, lethocerus indicus, metal binding protein
• Biological source: Lethocerus indicus
• Total number of polymer chains: 1
• Total formula weight: 17589.30

Authors

De Nicola, G.F.,Bullard, B.,Pastore, A. (deposition date: 2007-01-18, release date: 2007-08-07, Last modification date: 2023-12-20)

Primary citation

De Nicola, G.,Burkart, C.,Qiu, F.,Agianian, B.,Labeit, S.,Martin, S.,Bullard, B.,Pastore, A.
The structure of lethocerus troponin C: insights into the mechanism of stretch activation in muscles
Structure, 15:813-824, 2007

PubMed Abstract: To gain a molecular description of how muscles can be activated by mechanical stretch, we have solved the structure of the calcium-loaded F1 isoform of troponin C (TnC) from Lethocerus and characterized its interactions with troponin I (TnI). We show that the presence of only one calcium cation in the fourth EF hand motif is sufficient to induce an open conformation in the C-terminal lobe of F1 TnC, in contrast with what is observed in vertebrate muscle. This lobe interacts in a calcium-independent way both with the N terminus of TnI and, with lower affinity, with a region of TnI equivalent to the switch and inhibitory peptides of vertebrate muscles. Using both synthetic peptides and recombinant proteins, we show that the N lobe of F1 TnC is not engaged in interactions with TnI, excluding a regulatory role of this domain. These findings provide insights into mechanically stimulated muscle contraction.

PubMed: 17637342
DOI: 10.1016/j.str.2007.05.007

Experimental method

SOLUTION NMR