title: Actin-DBP: the perfect structural fit?
abstract: 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.
authors.affiliation: Laboratorium voor Analytische Chemie en Medicinale Fysicochemie, Faculteit Farmaceutische Wetenschappen, K. U. Leuven, Belgium.
authors.forename: Christel
authors.initials: C
authors.lastname: Verboven
authors.forename: Ilse
authors.initials: I
authors.lastname: Bogaerts
authors.forename: Etienne
authors.initials: E
authors.lastname: Waelkens
authors.forename: Anja
authors.initials: A
authors.lastname: Rabijns
authors.forename: Hugo
authors.initials: H
authors.lastname: Van Baelen
authors.forename: Roger
authors.initials: R
authors.lastname: Bouillon
authors.forename: Camiel
authors.initials: C
authors.lastname: De Ranter
mesh_terms: 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
chemical_list: D000199:Actins; D008840:Microfilament Proteins; D014809:Vitamin D-Binding Protein