Actin-DBP: the perfect structural fit?
The multifunctional vitamin D binding protein (DBP) is an actin-sequestering protein present in blood. The crystal structure of the actin-DBP complex was determined at 2.4 A resolution. DBP binds to actin subdomains 1 and 3 and occludes the cleft at the interface between these subdomains. Most remarkably, DBP demonstrates an unusually large actin-binding interface, far exceeding the binding-interface areas reported for other actin-binding proteins such as profilin, DNase I and gelsolin. The fast-growing side of actin monomers is blocked completely through a perfect structural fit with DBP, demonstrating how DBP effectively interferes with actin-filament formation. It establishes DBP as the hitherto best actin-sequestering protein and highlights its key role in suppressing and preventing extracellular actin polymerization.
Verboven
Christel
C
Laboratorium voor Analytische Chemie en Medicinale Fysicochemie, Faculteit Farmaceutische Wetenschappen, K. U. Leuven, Belgium.
Bogaerts
Ilse
I
Waelkens
Etienne
E
Rabijns
Anja
A
Van Baelen
Hugo
H
Bouillon
Roger
R
De Ranter
Camiel
C
D000199:Actins / Q000737:chemistry* / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D018360:Crystallography, X-Ray; D006801:Humans; D006860:Hydrogen Bonding; D008840:Microfilament Proteins / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D011817:Rabbits; D014809:Vitamin D-Binding Protein / Q000737:chemistry* / Q000378:metabolism
D000199:Actins; D008840:Microfilament Proteins; D014809:Vitamin D-Binding Protein