1tyq
From Proteopedia
Crystal structure of Arp2/3 complex with bound ATP and calcium
Structural highlights
Function[ARP3_BOVIN] Functions as ATP-binding component of the Arp2/3 complex which is involved in regulation of actin polymerization and together with an activating nucleation-promoting factor (NPF) mediates the formation of branched actin networks. Seems to contact the pointed end of the daughter actin filament. Plays a role in ciliogenesis (By similarity). Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedActin-related protein (Arp) 2/3 complex stimulates formation of actin filaments at the leading edge of motile cells. Nucleation of filaments depends on hydrolysis of ATP bound to Arp2. Here we report crystal structures of Arp2/3 complex with bound ATP or ADP. The nucleotides are immobilized on the face of subdomains 3 and 4 of Arp2, whereas subdomains 1 and 2 are flexible and absent from the electron density maps. This flexibility may explain why Arp2 does not hydrolyze ATP until the complex is activated. ATP stabilizes a relatively closed conformation of Arp3 with the gamma-phosphate bridging loops from opposite sides of the cleft. ADP binds Arp3 in a unique conformation that favors an open cleft, revealing a conformational change that may occur in actin and Arps when ATP is hydrolyzed and phosphate dissociates. These structures provide the an opportunity to compare all nucleotide-binding states in an actin-related protein and give insights into the function of both the Arp2/3 complex and actin. Crystal structures of actin-related protein 2/3 complex with bound ATP or ADP.,Nolen BJ, Littlefield RS, Pollard TD Proc Natl Acad Sci U S A. 2004 Nov 2;101(44):15627-32. Epub 2004 Oct 25. PMID:15505213[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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