5ly3
From Proteopedia
P. calidifontis crenactin in complex with arcadin-2 C-terminal peptide
Structural highlights
FunctionCREN1_PYRCJ Forms the backbone of an actin-like archaeal cytoskeleton, which is involved in cell shape determination. Has ATPase activity. Shows highest activity towards ATP or GTP as nucleotide, and only residual activity on UTP, CTP and dNTPs.[1] Publication Abstract from PubMedThe similarity of eukaryotic actin to crenactin, a filament-forming protein from the crenarchaeon Pyrobaculum calidifontis supports the theory of a common origin of Crenarchaea and Eukaryotes. Monomeric structures of crenactin and actin are similar, although their filament architectures were suggested to be different. Here we report that crenactin forms bona fide double helical filaments that show exceptional similarity to eukaryotic F-actin. With cryo-electron microscopy and helical reconstruction we solved the structure of the crenactin filament to 3.8 A resolution. When forming double filaments, the 'hydrophobic plug' loop in crenactin rearranges. Arcadin-2, also encoded by the arcade gene cluster, binds tightly with its C-terminus to the hydrophobic groove of crenactin. Binding is reminiscent of eukaryotic actin modulators such as cofilin and thymosin beta4 and arcadin-2 is a depolymeriser of crenactin filaments. Our work further supports the theory of shared ancestry of Eukaryotes and Crenarchaea. Crenactin forms actin-like double helical filaments regulated by arcadin-2.,Izore T, Kureisaite-Ciziene D, McLaughlin SH, Lowe J Elife. 2016 Nov 17;5. pii: e21600. doi: 10.7554/eLife.21600. PMID:27852434[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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