We investigated the muscle enzyme, titin kinase, by means of single- molecule force spectroscopy. Our results show that the binding of ATP, which is the first step of its signaling cascade controlling the muscle gene expression and protein turnover, is mechanically induced. The detailed determination of barrier positions in the mechanical activation pathway and the corresponding functional states allow structural insight by comparing the experiment with molecular dynamics simulations. From our results, we conclude that titin kinase acts as a natural force sensor controlling the muscle build-up. To study the interplay of functional units, we developed the single-molecule cut-and-paste technique which combines the precision of AFM with the selectivity of DNA hybridization. Functional units can be assembled one-by-one in an arbitrarily predefined pattern, with an accuracy that is better than 11 nm. The cyclic assembly process is optically monitored and mechanically recorded by force-extension traces. Using biotin as a functional unit attached to the transported DNA, patterns of binding sites may be created, to which streptavidin- modified nanoobjects like fluorescent nanoparticles can specifically self-assemble in a second step.
|Original language||English (US)|
|Title of host publication||Single Molecule Spectroscopy in Chemistry, Physics and Biology|
|Subtitle of host publication||Nobel Symposium|
|Publisher||Springer New York LLC|
|Number of pages||12|
|State||Published - 2010|
|Name||Springer Series in Chemical Physics|
Bibliographical noteFunding Information:
We thank S.K. Kufer, S. Stahl, M. Strackharn, H. Gumpp and M. Gautel, H. Grubmüller and their groups for collaborations and helpful discussions and SFB 486, Nanosystems Initiative Munich (NIM) and Center for Integrated Protein Science Munich (CIPSM) for financial support.