7kcn | pdb_00007kcn

Reconstructed ancestor of HIUases and Transthyretins

spinqualitylabelsall models 7kcn, resolution 1.46Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 7kcn is a 2 chain structure with sequence from Miscellaneous nucleic acid. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: EDO, PO4 Related: 7kjj Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed Transthyretin was discovered in the 1940s, named after its ability to bind thyroid hormones and retinol. In the genomic era, transthyretins were found to be part of a larger family with homologs of no obvious function, then called transthyretin-related proteins. Thus, it was proposed that the transthyretin gene could be the result of gene duplication of an ancestral of this newly identified homolog, later found out to be an enzyme involved in uric acid degradation, then named HIUase (5-hydroxy-isourate hydrolase). Here, we sought to re-enact the evolutionary history of this protein family by reconstructing, from a phylogeny inferred from 123 vertebrate sequences, three ancestors corresponding to key moments in their evolution-before duplication; the common transthyretin ancestor after gene duplication and the common ancestor of Eutheria transthyretins. Experimental and computational characterization showed the reconstructed ancestor before duplication was unable to bind thyroxine and likely presented the modern HIUase reaction mechanism, while the substitutions after duplication prevented that activity and were enough to provide stable thyroxine binding, as confirmed by calorimetry and x-ray diffraction. The Eutheria transthyretin ancestor was less prone to characterization, but limited data suggested thyroxine binding as expected. Sequence/structure analysis suggests an early ability to bind the Retinol Binding Protein. We solved the X-ray structures from the two first ancestors, the first at 1.46 resolution, the second at 1.55 resolution with well-defined electron density for thyroxine, providing a useful tool for the understanding of structural adaptation from enzyme to hormone distributor. Reenacting the Birth of a Function: Functional Divergence of HIUases and Transthyretins as Inferred by Evolutionary and Biophysical Studies.,Carrijo de Oliveira L, Figueiredo Costa MA, Goncalves Pedersolli N, Heleno Batista FA, Migliorini Figueira AC, Salgado Ferreira R, Alves Pinto Nagem R, Alves Nahum L, Bleicher L J Mol Evol. 2021 May 6. pii: 10.1007/s00239-021-10010-8. doi:, 10.1007/s00239-021-10010-8. PMID:33956179 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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