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This content will become publicly available on October 6, 2016

Title: On the protonation states, hydrogen bonding and catalytic mechanism of family 11 glycosidases: Direct visualization with neutrons

Most enzymatic reactions involve hydrogen or proton transfer among the enzyme, substrate, and water at physiological pH. Thus, enzyme catalysis cannot be fully understood without accurate mapping of hydrogen atom positions in these macromolecular catalysts. Direct information on the location of hydrogen atoms can be obtained using neutron crystallography. We used neutron crystallography and biomolecular simulation to characterize the initial stage of the glycoside hydrolysis reaction catalyzed by a family 11 glycoside hydrolase. We provide evidence that the catalytic glutamate residue alternates between two conformations bearing different basicities, first to obtain a proton from the bulk solvent, and then to deliver it to the glycosidic oxygen to initiate the hydrolysis reaction.
Authors:
 [1] ;  [2] ;  [3] ;  [2] ;  [2] ;  [2] ;  [2] ;  [4] ;  [4]
  1. European Spallation Source (ESS), Lund (Sweden)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  3. Univ. of Toledo, OH (United States)
  4. Technische Univ. Munchen, Garching (Germany)
Publication Date:
OSTI Identifier:
1240521
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America
Additional Journal Information:
Journal Volume: 112; Journal Issue: 40; Journal ID: ISSN 0027-8424
Publisher:
National Academy of Sciences, Washington, DC (United States)
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY