Skip to Main content Skip to Navigation
Journal articles

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

Abstract : Aminopeptidase A (APA) is a membrane-bound 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. Using a refined APA structure derived from the human APA crystal structure, we docked the specific and selective APA inhibitor, EC33 in the presence of Ca2+. We report the presence in the S1 subsite of Arg-887 (Arg-878 in mouse APA), the guanidinium moiety of which established an interaction with the electronegative sulfonate group of EC33. Mutagenic replacement of Arg-878 with an alanine or a lysine residue decreased the affinity of the recombinant enzymes for the acidic substrate, α-L-glutamyl-β-naphthylamide, with a slight decrease in substrate hydrolysis velocity either with or without 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, although the addition of Ca2+ partially restored the acidic substrate specificity. The analysis of the 3D models of the Arg-878 mutated APAs 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 the key role of Arg-878 together with Ca2 + in APA substrate specificity for N-terminal acidic amino acid residues by ensuring the optimal positioning of acidic substrates during catalysis.
Complete list of metadata

https://hal.inria.fr/hal-01580832
Contributor : Bernard Maigret Connect in order to contact the contributor
Submitted on : Saturday, September 2, 2017 - 9:30:11 PM
Last modification on : Friday, July 8, 2022 - 10:05:08 AM

Links full text

Identifiers

Citation

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, 12 (9), pp.e0184237. ⟨10.1371/journal.pone.0184237⟩. ⟨hal-01580832⟩

Share

Metrics

Record views

268