4cbw | pdb_00004cbw

Crystal structure of Plasmodium berghei actin I with D-loop from muscle actin

spinqualitylabelsall models 4cbw, resolution 2.50Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4cbw is a 2 chain structure with sequence from Lk3 transgenic mice and Plabe. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: ATP, CA, DIO Related: 4cbu, 4cbx Resources: FirstGlance, OCA, RCSB, PDBsum Function [ACT1_PLABA] Actins are highly conserved proteins that are involved in various types of cell motility and are ubiquitously expressed in all eukaryotic cells. [GELS_MOUSE] Calcium-regulated, actin-modulating protein that binds to the plus (or barbed) ends of actin monomers or filaments, preventing monomer exchange (end-blocking or capping). It can promote the assembly of monomers into filaments (nucleation) as well as sever filaments already formed. Plays a role in ciliogenesis. Publication Abstract from PubMed Actins are highly conserved proteins and key players in central processes in all eukaryotic cells. The two actins of the malaria parasite are among the most divergent eukaryotic actins and also differ from each other more than isoforms in any other species. Microfilaments have not been directly observed in Plasmodium and are presumed to be short and highly dynamic. We show that actin I cannot complement actin II in male gametogenesis, suggesting critical structural differences. Cryo-EM reveals that Plasmodium actin I has a unique filament structure, whereas actin II filaments resemble canonical F-actin. Both Plasmodium actins hydrolyze ATP more efficiently than alpha-actin, and unlike any other actin, both parasite actins rapidly form short oligomers induced by ADP. Crystal structures of both isoforms pinpoint several structural changes in the monomers causing the unique polymerization properties. Inserting the canonical D-loop to Plasmodium actin I leads to the formation of long filaments in vitro. In vivo, this chimera restores gametogenesis in parasites lacking actin II, suggesting that stable filaments are required for exflagellation. Together, these data underline the divergence of eukaryotic actins and demonstrate how structural differences in the monomers translate into filaments with different properties, implying that even eukaryotic actins have faced different evolutionary pressures and followed different paths for developing their polymerization properties. Structural differences explain diverse functions of Plasmodium actins.,Vahokoski J, Bhargav SP, Desfosses A, Andreadaki M, Kumpula EP, Martinez SM, Ignatev A, Lepper S, Frischknecht F, Siden-Kiamos I, Sachse C, Kursula I PLoS Pathog. 2014 Apr 17;10(4):e1004091. doi: 10.1371/journal.ppat.1004091., eCollection 2014 Apr. PMID:24743229 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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