2zal
Crystal structure of E. coli isoaspartyl aminopeptidase/L-asparaginase in complex with L-aspartate
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 PubMedThe crystal structure of Escherichia coli isoaspartyl aminopeptidase/asparaginase (EcAIII), an enzyme belonging to the N-terminal nucleophile (Ntn)-hydrolases family, has been determined at 1.9-A resolution for a complex obtained by cocrystallization with l-aspartate, which is a product of both enzymatic reactions catalyzed by EcAIII. The enzyme is a dimer of heterodimers, (alphabeta)(2). The (alphabeta) heterodimer, which arises by autoproteolytic cleavage of the immature protein, exhibits an alphabetabetaalpha-sandwich fold, typical for Ntn-hydrolases. The asymmetric unit contains one copy of the EcAIII.Asp complex, with clearly visible l-aspartate ligands, one bound in each of the two active sites of the enzyme. The l-aspartate ligand is located near Thr(179), the N-terminal residue of subunit beta liberated in the autoproteolytic event. Structural comparisons with the free form of EcAIII reveal that there are no major rearrangements of the active site upon aspartate binding. Although the ligand binding mode is similar to that observed in an l-aspartate complex of the related enzyme human aspartylglucosaminidase, the architecture of the EcAIII active site sheds light on the question of substrate specificity and explains why EcAIII is not able to hydrolyze glycosylated asparagine substrates. Crystal structure of isoaspartyl aminopeptidase in complex with L-aspartate.,Michalska K, Brzezinski K, Jaskolski M J Biol Chem. 2005 Aug 5;280(31):28484-91. Epub 2005 Jun 9. PMID:15946951[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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