2jnf
Solution structure of fly troponin C, isoform F1
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OverviewOverview
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.
About this StructureAbout this Structure
2JNF is a Single protein structure of sequence from Lethocerus indicus. Full crystallographic information is available from OCA.
ReferenceReference
The structure of Lethocerus troponin C: insights into the mechanism of stretch activation in muscles., De Nicola G, Burkart C, Qiu F, Agianian B, Labeit S, Martin S, Bullard B, Pastore A, Structure. 2007 Jul;15(7):813-24. PMID:17637342
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