1k2x
Crystal structure of putative asparaginase encoded by Escherichia coli ybiK gene
Structural highlights
FunctionIAAA_ECOLI Degrades proteins damaged by L-isoaspartyl residue formation (also known as beta-Asp residues). Degrades L-isoaspartyl-containing di- and maybe also tripeptides. Also has L-asparaginase activity, although this may not be its principal function.[1] May be involved in glutathione, and possibly other peptide, transport, although these results could also be due to polar effects of disruption.[2] 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 PubMedPlant-type L-asparaginases hydrolyze the side-chain amide bond of L-asparagine or its beta-peptides. They belong to the N-terminal nucleophile (Ntn) hydrolases and are synthesized as inactive precursor molecules. Activation occurs via the autoproteolytic release of two subunits, alpha and beta, the latter of which carries the nucleophile at its N-terminus. Crystallographic studies of plant-type asparaginases have focused on an Escherichia coli homologue (EcAIII), which has been crystallized in several crystal forms. Although they all belong to the same P2 1 2 1 2 1 space group with similar unit-cell parameters, they display different crystal-packing arrangements and thus should be classified as separate polymorphs. This variability stems mainly from different positions of the EcAIII molecules within the unit cell, although they also exhibit slight differences in orientation. The intermolecular interactions that trigger different crystal lattice formation are mediated by ions, which represent the most variable component of the crystallization conditions. This behaviour confirms recent observations that small molecules might promote protein crystal lattice formation. Crystal packing of plant-type L-asparaginase from Escherichia coli.,Michalska K, Borek D, Hernandez-Santoyo A, Jaskolski M Acta Crystallogr D Biol Crystallogr. 2008 Mar;64(Pt 3):309-20. Epub 2008, Feb 20. PMID:18323626[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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