Structure of the alpha-actinin-vinculin head domain complex determined by cryo-electron microscopy.
The vinculin binding site on alpha-actinin was determined by cryo-electron microscopy of 2D arrays formed on phospholipid monolayers doped with a nickel chelating lipid. Chicken smooth muscle alpha-actinin was cocrystallized with the beta1-integrin cytoplasmic domain and a vinculin fragment containing residues 1-258 (vinculin(D1)). Vinculin(D1) was located at a single site on alpha-actinin with 60-70% occupancy. In these arrays, alpha-actinin lacks molecular 2-fold symmetry and the two ends of the molecule, which contain the calmodulin-like and actin binding domains, are held in distinctly different environments. The vinculin(D1) difference density has a shape very suggestive of the atomic structure. The atomic model of the complex juxtaposes the alpha-actinin binding site on vinculin(D1) with the N-terminal lobe of the calmodulin-like domain on alpha-actinin. The results show that the interaction between two species with weak affinity can be visualized in a membrane-like environment.
Kelly
Deborah F
DF
Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306-4380, USA.
Taylor
Dianne W
DW
Bakolitsa
Constantina
C
Bobkov
Andrey A
AA
Bankston
Laurie
L
Liddington
Robert C
RC
Taylor
Kenneth A
KA
D000185:Actinin / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D000199:Actins / Q000737:chemistry / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D002152:Calorimetry, Differential Scanning; D002645:Chickens; D020285:Cryoelectron Microscopy; D006801:Humans; D019012:Integrin beta1 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes; D011485:Protein Binding; D011487:Protein Conformation; D016608:Talin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016596:Vinculin / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
D000199:Actins; D019012:Integrin beta1; D046912:Multiprotein Complexes; D016608:Talin; D000185:Actinin; D016596:Vinculin