2qr5

Aeropyrum pernix acylaminoacyl peptidase, H367A mutant

spinqualitylabelsall models 2qr5, resolution 2.20Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2qr5 is a 2 chain structure with sequence from Aeropyrum pernix. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Activity: Acylaminoacyl-peptidase, with EC number 3.4.19.1 Resources: FirstGlance, OCA, RCSB, PDBsum Function [APEH_AERPE] This enzyme catalyzes the hydrolysis of the N-terminal peptide bond of an N-acetylated peptide to generate an N-acetylated amino acid and a peptide with a free N-terminus. 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 PubMed It is widely accepted that the catalytic activity of serine proteases depends primarily on the Asp-His-Ser catalytic triad and other residues within the vicinity of this motif. Some of these residues form the oxyanion binding site that stabilizes the tetrahedral intermediate by hydrogen bonding to the negatively charged oxyanion. In acylaminoacyl peptidase from the thermophile Aeropyrum pernix, the main chain NH group of Gly369 is one of the hydrogen bond donors forming the oxyanion binding site. The side chain of His367, a conserved residue in acylaminoacyl peptidases across all species, fastens the loop holding Gly369. Determination of the crystal structure of the H367A mutant revealed that this loop, including Gly369, moves away considerably, accounting for the observed three orders of magnitude decrease in the specificity rate constant. For the wild-type enzyme ln(k(cat)/K(m)) vs. 1/T deviates from linearity indicating greater rate enhancement with increasing temperature for the dissociation of the enzyme-substrate complex compared with its decomposition to product. In contrast, the H367A variant provided a linear Arrhenius plot, and its reaction was associated with unfavourable entropy of activation. These results show that a residue relatively distant from the active site can significantly affect the catalytic activity of acylaminoacyl peptidase without changing the overall structure of the enzyme. Structural and kinetic contributions of the oxyanion binding site to the catalytic activity of acylaminoacyl peptidase.,Kiss AL, Pallo A, Naray-Szabo G, Harmat V, Polgar L J Struct Biol. 2008 May;162(2):312-23. Epub 2008 Feb 2. PMID:18325786 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Acylaminoacyl peptidase

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