Involvement of arginine 878 together with Ca2+ in aminopeptidase A substrate specificity for N-terminal acidic amino-acid residues.

Pierre Couvineau 1 Hugo De Almeida 2 Bernard Maigret 3 Catherine Llorens-Cortes 4 Xavier Iturrioz 4
2 ORPAILLEUR - Knowledge representation, reasonning
Inria Nancy - Grand Est, LORIA - NLPKD - Department of Natural Language Processing & Knowledge Discovery
3 CAPSID - Computational Algorithms for Protein Structures and Interactions
Inria Nancy - Grand Est, LORIA - AIS - Department of Complex Systems, Artificial Intelligence & Robotics
Abstract : Aminopeptidase A (APA) is a membranebound zinc metalloprotease cleaving in the brain the N-terminal aspartyl residue of angiotensin II to generate angiotensin III, which exerts a tonic stimulatory effect on the control of blood pressure in hypertensive animals. We built by homology a threedimensional (3D) model of human APA with Ca2+ using the crystal structure of human APA as a template and we subsequently docked the APA inhibitor EC33 [(3S)-3-amino-4-sulfanylbutane-1-sulfonic acid]. We report the presence in the S1 subsite of Arg-887 (Arg-878 in mouse APA), the guanidium moiety of which established an interaction with the electronegative sulfonate group of EC33. Mutagenic replacement of Arg-878 with an alanine or lysine residue led to a decrease in the affinity of the recombinant enzymes for the acidic substrate, α-L-glutamyl-β- naphthylamide, with a slight decrease in substrate hydrolysis velocity either in the absence or presence of Ca2+. In the absence of Ca2+, the mutations modified the substrate specificity of APA for the acidic substrate, the mutated enzymes hydrolyzing more efficiently basic and neutral substrates, nevertheless the addition of Ca2+ partially restored their acidic substrate specificity. An analysis of the 3D models of the Arg-878 mutants revealed a change in the volume of the S1 subsite, which may impair the binding and/or the optimal positioning of the substrate in the active site as well as its hydrolysis. These findings demonstrate a key role of Arg-878 in APA substrate specificity for N-terminal acidic amino acids by insuring the optimal positioning of the substrate during catalysis.
Type de document :
Article dans une revue
PLoS ONE, Public Library of Science, 2017
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https://hal.inria.fr/hal-01580832
Contributeur : Bernard Maigret <>
Soumis le : samedi 2 septembre 2017 - 21:30:11
Dernière modification le : jeudi 11 janvier 2018 - 06:27:31

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  • HAL Id : hal-01580832, version 1

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Pierre Couvineau, Hugo De Almeida, Bernard Maigret, Catherine Llorens-Cortes, Xavier Iturrioz. Involvement of arginine 878 together with Ca2+ in aminopeptidase A substrate specificity for N-terminal acidic amino-acid residues.. PLoS ONE, Public Library of Science, 2017. 〈hal-01580832〉

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