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Photo Lynn Kamerlin

Lynn Kamerlin

Professor

Photo Lynn Kamerlin

Insights into the importance of WPD-loop sequence for activity and structure in protein tyrosine phosphatases

Author

  • Ruidan Shen
  • Rory M Crean
  • Keith J Olsen
  • Marina Corbella
  • Ana R Calixto
  • Teisha Richan
  • Tiago A S Brandão
  • Ryan D Berry
  • Alex Tolman
  • J Patrick Loria
  • Sean J Johnson
  • Shina C L Kamerlin
  • Alvan C Hengge
Show all

Summary, in English

Protein tyrosine phosphatases (PTPs) possess a conserved mobile catalytic loop, the WPD-loop, which brings an aspartic acid into the active site where it acts as an acid/base catalyst. Prior experimental and computational studies, focused on the human enzyme PTP1B and the PTP from Yersinia pestis, YopH, suggested that loop conformational dynamics are important in regulating both catalysis and evolvability. We have generated a chimeric protein in which the WPD-loop of YopH is transposed into PTP1B, and eight chimeras that systematically restored the loop sequence back to native PTP1B. Of these, four chimeras were soluble and were subjected to detailed biochemical and structural characterization, and a computational analysis of their WPD-loop dynamics. The chimeras maintain backbone structural integrity, with somewhat slower rates than either wild-type parent, and show differences in the pH dependency of catalysis, and changes in the effect of Mg2+. The chimeric proteins' WPD-loops differ significantly in their relative stability and rigidity. The time required for interconversion, coupled with electrostatic effects revealed by simulations, likely accounts for the activity differences between chimeras, and relative to the native enzymes. Our results further the understanding of connections between enzyme activity and the dynamics of catalytically important groups, particularly the effects of non-catalytic residues on key conformational equilibria.

Publishing year

2022-11-23

Language

English

Pages

13524-13540

Publication/Series

Chemical Science

Volume

13

Issue

45

Document type

Journal article

Publisher

Royal Society of Chemistry

Status

Published

ISBN/ISSN/Other

  • ISSN: 2041-6520