3cip

Complex of Dictyostelium Discoideum Actin with Gelsolin

spinqualitylabelsall models 3cip, resolution 1.60Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3cip is a 2 chain structure with sequence from Dictyostelium discoideum and Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.6Å Ligands: ATP, CA, GOL, HIC, MG, SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function ACT1_DICDI 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 PubMed On starvation, Dictyostelium cells aggregate to form multicellular fruiting bodies containing spores that germinate when transferred to nutrient-rich medium. This developmental cycle correlates with the extent of actin phosphorylation at Tyr-53 (pY53-actin), which is low in vegetative cells but high in viable mature spores. Here we describe high-resolution crystal structures of pY53-actin and unphosphorylated actin in complexes with gelsolin segment 1 and profilin. In the structure of pY53-actin, the phosphate group on Tyr-53 makes hydrogen-bonding interactions with residues of the DNase I-binding loop (D-loop) of actin, resulting in a more stable conformation of the D-loop than in the unphosphorylated structures. A more rigidly folded D-loop may explain some of the previously described properties of pY53-actin, including its increased critical concentration for polymerization, reduced rates of nucleation and pointed end elongation, and weak affinity for DNase I. We show here that phosphorylation of Tyr-53 inhibits subtilisin cleavage of the D-loop and reduces the rate of nucleotide exchange on actin. The structure of profilin-Dictyostelium-actin is strikingly similar to previously determined structures of profilin-beta-actin and profilin-alpha-actin. By comparing this representative set of profilin-actin structures with other structures of actin, we highlight the effects of profilin on the actin conformation. In the profilin-actin complexes, subdomains 1 and 3 of actin close around profilin, producing a 4.7 degrees rotation of the two major domains of actin relative to each other. As a result, the nucleotide cleft becomes moderately more open in the profilin-actin complex, probably explaining the stimulation of nucleotide exchange on actin by profilin. Modulation of actin structure and function by phosphorylation of Tyr-53 and profilin binding.,Baek K, Liu X, Ferron F, Shu S, Korn ED, Dominguez R Proc Natl Acad Sci U S A. 2008 Aug 8. PMID:18689676 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Actin 3D structures Gelsolin 3D structures

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