کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
2030754 | 1071244 | 2007 | 12 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: The Structure of Lethocerus Troponin C: Insights into the Mechanism of Stretch Activation in Muscles The Structure of Lethocerus Troponin C: Insights into the Mechanism of Stretch Activation in Muscles](/preview/png/2030754.png)
SummaryTo 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.
Journal: - Volume 15, Issue 7, 18 July 2007, Pages 813–824