Szeltner, Zoltán, Juhász, Tünde, Szamosi, Ilona, Rea, Dean, Fülöp, Vilmos, Módos, Károly, Juliano, Luiz and Polgár, László (2013) The loops facing the active site of prolyl oligopeptidase are crucial components in substrate gating and specificity. Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics, Vol.1834 (No.1). pp. 98-111. doi:10.1016/j.bbapap.2012.08.012

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Abstract

Prolyl oligopeptidase (POP) has emerged as a drug target for neurological diseases. A flexible loop structure comprising loop A (res. 189–209) and loop B (res. 577–608) at the domain interface is implicated in substrate entry to the active site. Here we determined kinetic and structural properties of POP with mutations in loop A, loop B, and in two additional flexible loops (the catalytic His loop, propeller Asp/Glu loop). POP lacking loop A proved to be an inefficient enzyme, as did POP with a mutation in loop B (T590C). Both variants displayed an altered substrate preference profile, with reduced ligand binding capacity. Conversely, the T202C mutation increased the flexibility of loop A, enhancing the catalytic efficiency beyond that of the native enzyme. The T590C mutation in loop B increased the preference for shorter peptides, indicating a role in substrate gating. Loop A and the His loop are disordered in the H680A mutant crystal structure, as seen in previous bacterial POP structures, implying coordinated structural dynamics of these loops. Unlike native POP, variants with a malfunctioning loop A were not inhibited by a 17-mer peptide that may bind non-productively to an exosite involving loop A. Biophysical studies suggest a predominantly closed resting state for POP with higher flexibility at the physiological temperature. The flexible loop A, loop B and His loop system at the active site is the main regulator of substrate gating and specificity and represents a new inhibitor target.

Item Type:	Journal Article
Subjects:	Q Science > QH Natural history > QH301 Biology
Divisions:	Faculty of Science > Life Sciences (2010- )
Library of Congress Subject Headings (LCSH):	Peptidase, Drug targeting, Protein engineering
Journal or Publication Title:	Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics
Publisher:	Elsevier BV
ISSN:	1570-9639
Official Date:	January 2013
Dates:	Date Event January 2013 Published
Date of first compliant deposit:	23 December 2015
Volume:	Vol.1834
Number:	No.1
Page Range:	pp. 98-111
DOI:	10.1016/j.bbapap.2012.08.012
Status:	Peer Reviewed
Publication Status:	Published
Access rights to Published version:	Restricted or Subscription Access
Funder:	Birmingham Science City, Advantage West Midlands (AWM)

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