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SHP-1 Variants Broaden the Understanding of pH-Dependent Activities in Protein Tyrosine Phosphatases

Shen, Ruidan ; Brownless, Alfie-Louise R ; Alansson, Nikolas ; Corbella, Marina ; Kamerlin, Shina C L LU orcid and Hengge, Alvan C (2024) In JACS Au 4(8). p.2874-2885
Abstract

The protein tyrosine phosphatase (PTP) SHP-1 plays an important role in both immune regulation and oncogenesis. This enzyme is part of a broader family of PTPs that all play important regulatory roles in vivo. Common to these enzymes is a highly conserved aspartic acid (D421 in SHP-1) that acts as an acid/base catalyst during the PTP-catalyzed reaction. This residue is located on a mobile loop, the WPD-loop, the dynamic behavior of which is intimately connected to the catalytic activity. The SHP-1 WPD-loop variants H422Q, E427A, and S418A have been kinetically characterized and compared to those of the wild-type (WT) enzyme. These variants exhibit limiting magnitudes of k cat ranging from 43 to 77% of the WT enzyme. However, their pH... (More)

The protein tyrosine phosphatase (PTP) SHP-1 plays an important role in both immune regulation and oncogenesis. This enzyme is part of a broader family of PTPs that all play important regulatory roles in vivo. Common to these enzymes is a highly conserved aspartic acid (D421 in SHP-1) that acts as an acid/base catalyst during the PTP-catalyzed reaction. This residue is located on a mobile loop, the WPD-loop, the dynamic behavior of which is intimately connected to the catalytic activity. The SHP-1 WPD-loop variants H422Q, E427A, and S418A have been kinetically characterized and compared to those of the wild-type (WT) enzyme. These variants exhibit limiting magnitudes of k cat ranging from 43 to 77% of the WT enzyme. However, their pH profiles are significantly broadened in the basic pH range. As a result, above pH 6, the E427A and S418A variants have turnover numbers notably higher than those of WT SHP-1. Molecular modeling results indicate that the shifted pH dependencies result primarily from changes in solvation and hydrogen-bonding networks that affect the pK a of the D421 residue, explaining the changes in pH-rate profiles for k cat on the basic side. In contrast, a previous study of a noncatalytic residue variant of the PTP YopH, which also exhibited changes in pH dependency, showed that the catalytic change arose from mutation-induced changes in conformational equilibria of the WPD-loop. This finding and the present study show the existence of distinct strategies for nature to tune the activity of PTPs in particular environments through controlling the pH dependency of catalysis.

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author
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publishing date
type
Contribution to journal
publication status
published
in
JACS Au
volume
4
issue
8
pages
12 pages
publisher
The American Chemical Society (ACS)
external identifiers
  • scopus:85198931731
  • pmid:39211599
ISSN
2691-3704
DOI
10.1021/jacsau.4c00078
language
English
LU publication?
no
additional info
© 2024 The Authors. Published by American Chemical Society.
id
25c17c83-c8fb-4971-b7a2-9b4ada221303
date added to LUP
2025-01-11 18:13:08
date last changed
2025-07-27 19:30:45
@article{25c17c83-c8fb-4971-b7a2-9b4ada221303,
  abstract     = {{<p>The protein tyrosine phosphatase (PTP) SHP-1 plays an important role in both immune regulation and oncogenesis. This enzyme is part of a broader family of PTPs that all play important regulatory roles in vivo. Common to these enzymes is a highly conserved aspartic acid (D421 in SHP-1) that acts as an acid/base catalyst during the PTP-catalyzed reaction. This residue is located on a mobile loop, the WPD-loop, the dynamic behavior of which is intimately connected to the catalytic activity. The SHP-1 WPD-loop variants H422Q, E427A, and S418A have been kinetically characterized and compared to those of the wild-type (WT) enzyme. These variants exhibit limiting magnitudes of k cat ranging from 43 to 77% of the WT enzyme. However, their pH profiles are significantly broadened in the basic pH range. As a result, above pH 6, the E427A and S418A variants have turnover numbers notably higher than those of WT SHP-1. Molecular modeling results indicate that the shifted pH dependencies result primarily from changes in solvation and hydrogen-bonding networks that affect the pK a of the D421 residue, explaining the changes in pH-rate profiles for k cat on the basic side. In contrast, a previous study of a noncatalytic residue variant of the PTP YopH, which also exhibited changes in pH dependency, showed that the catalytic change arose from mutation-induced changes in conformational equilibria of the WPD-loop. This finding and the present study show the existence of distinct strategies for nature to tune the activity of PTPs in particular environments through controlling the pH dependency of catalysis.</p>}},
  author       = {{Shen, Ruidan and Brownless, Alfie-Louise R and Alansson, Nikolas and Corbella, Marina and Kamerlin, Shina C L and Hengge, Alvan C}},
  issn         = {{2691-3704}},
  language     = {{eng}},
  month        = {{08}},
  number       = {{8}},
  pages        = {{2874--2885}},
  publisher    = {{The American Chemical Society (ACS)}},
  series       = {{JACS Au}},
  title        = {{SHP-1 Variants Broaden the Understanding of pH-Dependent Activities in Protein Tyrosine Phosphatases}},
  url          = {{http://dx.doi.org/10.1021/jacsau.4c00078}},
  doi          = {{10.1021/jacsau.4c00078}},
  volume       = {{4}},
  year         = {{2024}},
}