An atomic model of fimbrin binding to F-actin and its implications for filament crosslinking and regulation.
Using a new procedure that combines electron-density correlation with biochemical information, we have fitted the crystal structure of the N-terminal actin-binding domain of human T-fimbrin to helical reconstructions of fimbrin-decorated actin filaments. The map locates the N-terminal calcium-binding domain and identifies actin-binding site residues on the two calponin-homology domains of fimbrin. Based on this map, we propose a model of a fimbrin crosslink in an actin bundle and its regulation by calcium.
Hanein
D
D
The W.M. Keck Institute for Cellular Visualization, Brandeis University, Waltham, Massachusetts 02254, USA. hanein@hydra.rose.brandeis.edu
Volkmann
N
N
Goldsmith
S
S
Michon
A M
AM
Lehman
W
W
Craig
R
R
DeRosier
D
D
Almo
S
S
Matsudaira
P
P
D000199:Actins / Q000737:chemistry* / Q000378:metabolism*; D000595:Amino Acid Sequence; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000737:chemistry; D003432:Cross-Linking Reagents; D018360:Crystallography, X-Ray; D004563:Electrochemistry; D006801:Humans; D066298:In Vitro Techniques; D008562:Membrane Glycoproteins / Q000737:chemistry* / Q000378:metabolism*; D008840:Microfilament Proteins; D008958:Models, Molecular; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D000096985:Calponins
D000199:Actins; D002118:Calcium; D002135:Calcium-Binding Proteins; D003432:Cross-Linking Reagents; D008562:Membrane Glycoproteins; D008840:Microfilament Proteins; D000096985:Calponins; C026742:plastin