Crystal Structure of Arp2/3 Complex
Abstract
We determined a crystal structure of bovine Arp2/3 complex, an assembly of seven proteins that initiates actin polymerization in eukaryotic cells, at 2.0 angstrom resolution. Actin-related protein 2 (Arp2) and Arp3 are folded like actin, with distinctive surface features. Subunits ARPC2 p34 and ARPC4 p20 in the core of the complex associate through long carboxyl-terminal α helices and have similarly folded amino-terminal α/β domains. ARPC1 p40 is a seven-blade β propeller with an insertion that may associate with the side of an actin filament. ARPC3 p21 and ARPC5 p16 are globular α-helical subunits. We predict that WASp/Scar proteins activate Arp2/3 complex by bringing Arp2 into proximity with Arp3 for nucleation of a branch on the side of a preexisting actin filament.
- Publication:
-
Science
- Pub Date:
- November 2001
- DOI:
- 10.1126/science.1066333
- Bibcode:
- 2001Sci...294.1679R
- Keywords:
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- BIOCHEM