3qo5 | pdb_00003qo5

Crystal Structure of the seryl-tRNA synthetase from Candida albicans

spinqualitylabelsall models 3qo5, resolution 2.30Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3qo5 is a 1 chain structure with sequence from candida_stellatoidea Atcc 11006 candida stellatoidea. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Related: 3qne, 3qo7, 3qo8 Gene: SES1, CaO19.7901 (ATCC 11006 Candida stellatoidea) Activity: Serine--tRNA ligase, with EC number 6.1.1.11 Resources: FirstGlance, OCA, RCSB, PDBsum Function [SYSC_CANAL] Catalyzes the attachment of serine to tRNA(Ser). Is also probably able to aminoacylate tRNA(Sec) with serine, to form the misacylated tRNA L-seryl-tRNA(Sec), which will be further converted into selenocysteinyl-tRNA(Sec). Publication Abstract from PubMed In a restricted group of opportunistic fungal pathogens the universal leucine CUG codon is translated both as serine (97%) and leucine (3%), challenging the concept that translational ambiguity has a negative impact in living organisms. To elucidate the molecular mechanisms underlying the in vivo tolerance to a nonconserved genetic code alteration, we have undertaken an extensive structural analysis of proteins containing CUG-encoded residues and solved the crystal structures of the two natural isoforms of Candida albicans seryl-tRNA synthetase. We show that codon reassignment resulted in a nonrandom genome-wide CUG redistribution tailored to minimize protein misfolding events induced by the large-scale leucine-to-serine replacement within the CTG clade. Leucine or serine incorporation at the CUG position in C. albicans seryl-tRNA synthetase induces only local structural changes and, although both isoforms display tRNA serylation activity, the leucine-containing isoform is more active. Similarly, codon ambiguity is predicted to shape the function of C. albicans proteins containing CUG-encoded residues in functionally relevant positions, some of which have a key role in signaling cascades associated with morphological changes and pathogenesis. This study provides a first detailed analysis on natural reassignment of codon identity, unveiling a highly dynamic evolutionary pattern of thousands of fungal CUG codons to confer an optimized balance between protein structural robustness and functional plasticity. Unveiling the structural basis for translational ambiguity tolerance in a human fungal pathogen.,Rocha R, Pereira PJ, Santos MA, Macedo-Ribeiro S Proc Natl Acad Sci U S A. 2011 Aug 8. PMID:21825144 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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