Evidence for an Interaction between the SH3 Domain and the N-terminal Extension of the Essential Light Chain in Class II Myosins

@article{citeulike:2681055, abstract = {The function of the src-homology 3 (SH3) domain in class II myosins, a distinct [beta]-barrel structure, remains unknown. Here, we provide evidence, using electron cryomicroscopy, in conjunction with light-scattering, fluorescence and kinetic analyses, that the SH3 domain facilitates the binding of the N-terminal extension of the essential light chain isoform (ELC-1) to actin. The 41 residue extension contains four conserved lysine residues followed by a repeating sequence of seven Pro/Ala residues. It is widely believed that the highly charged region interacts with actin, while the Pro/Ala-rich sequence forms a rigid tether that bridges the ~ 9 nm distance between the myosin lever arm and the thin filament. In order to localize the N terminus of ELC in the actomyosin complex, an engineered Cys was reacted with undecagold-maleimide, and the labeled ELC was exchanged into myosin subfragment-1 (S1). Electron cryomicroscopy of S1-bound actin filaments, together with computer-based docking of the skeletal S1 crystal structure into 3D reconstructions, showed a well-defined peak for the gold cluster near the SH3 domain. Given that SH3 domains are known to bind proline-rich ligands, we suggest that the N-terminal extension of ELC interacts with actin and modulates myosin kinetics by binding to the SH3 domain during the ATPase cycle.}, author = {Lowey, Susan and Saraswat, Lakshmi D. and Liu, Hongjun and Volkmann, Niels and Hanein, Dorit }, citeulike-article-id = {2681055}, doi = {10.1016/j.jmb.2007.05.080}, journal = {Journal of Molecular Biology}, keywords = {clip, em, experiment, fret, motor, myosin}, month = {August}, number = {4}, pages = {902--913}, posted-at = {2008-04-17 09:31:04}, priority = {2}, title = {Evidence for an Interaction between the SH3 Domain and the N-terminal Extension of the Essential Light Chain in Class II Myosins}, url = {http://dx.doi.org/10.1016/j.jmb.2007.05.080}, volume = {371}, year = {2007} }

TY - JOUR ID - citeulike:2681055 L3 - citeulike-article-id:2681055 TI - Evidence for an Interaction between the SH3 Domain and the N-terminal Extension of the Essential Light Chain in Class II Myosins JF - Journal of Molecular Biology VL - 371 IS - 4 SP - 902 EP - 913 N2 - The function of the src-homology 3 (SH3) domain in class II myosins, a distinct [beta]-barrel structure, remains unknown. Here, we provide evidence, using electron cryomicroscopy, in conjunction with light-scattering, fluorescence and kinetic analyses, that the SH3 domain facilitates the binding of the N-terminal extension of the essential light chain isoform (ELC-1) to actin. The 41 residue extension contains four conserved lysine residues followed by a repeating sequence of seven Pro/Ala residues. It is widely believed that the highly charged region interacts with actin, while the Pro/Ala-rich sequence forms a rigid tether that bridges the ~ 9 nm distance between the myosin lever arm and the thin filament. In order to localize the N terminus of ELC in the actomyosin complex, an engineered Cys was reacted with undecagold-maleimide, and the labeled ELC was exchanged into myosin subfragment-1 (S1). Electron cryomicroscopy of S1-bound actin filaments, together with computer-based docking of the skeletal S1 crystal structure into 3D reconstructions, showed a well-defined peak for the gold cluster near the SH3 domain. Given that SH3 domains are known to bind proline-rich ligands, we suggest that the N-terminal extension of ELC interacts with actin and modulates myosin kinetics by binding to the SH3 domain during the ATPase cycle. KW - clip KW - em KW - experiment KW - fret KW - motor KW - myosin AU - Lowey, Susan AU - Saraswat, Lakshmi AU - Liu, Hongjun AU - Volkmann, Niels AU - Hanein, Dorit PY - 2007/08/24/ UR - http://dx.doi.org/10.1016/j.jmb.2007.05.080 ER -