Conformational motions regulate phosphoryl transfer in related protein tyrosine phosphatases

Science. 2013 Aug 23;341(6148):899-903. doi: 10.1126/science.1241735.

Abstract

Many studies have implicated a role for conformational motions during the catalytic cycle, acting to optimize the binding pocket or facilitate product release, but a more intimate role in the chemical reaction has not been described. We address this by monitoring active-site loop motion in two protein tyrosine phosphatases (PTPs) using nuclear magnetic resonance spectroscopy. The PTPs, YopH and PTP1B, have very different catalytic rates; however, we find in both that the active-site loop closes to its catalytically competent position at rates that mirror the phosphotyrosine cleavage kinetics. This loop contains the catalytic acid, suggesting that loop closure occurs concomitantly with the protonation of the leaving group tyrosine and explains the different kinetics of two otherwise chemically and mechanistically indistinguishable enzymes.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Bacterial Outer Membrane Proteins / chemistry*
  • Catalysis
  • Catalytic Domain
  • Humans
  • Motion
  • Nuclear Magnetic Resonance, Biomolecular
  • Phosphates / chemistry*
  • Protein Conformation
  • Protein Tyrosine Phosphatase, Non-Receptor Type 1 / chemistry*
  • Protein Tyrosine Phosphatases / chemistry*
  • Vanadates / chemistry

Substances

  • Bacterial Outer Membrane Proteins
  • Phosphates
  • Vanadates
  • Protein Tyrosine Phosphatase, Non-Receptor Type 1
  • Protein Tyrosine Phosphatases
  • yopH protein, Yersinia