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A GAP‐GTPase‐GDP‐P(i) Intermediate Crystal Structure Analyzed by DFT Shows GTP Hydrolysis Involves Serial Proton Transfers

Cell signaling by small G proteins uses an ON to OFF signal based on conformational changes following the hydrolysis of GTP to GDP and release of dihydrogen phosphate (P(i)). The catalytic mechanism of GTP hydrolysis by RhoA is strongly accelerated by a GAP protein and is now well defined, but timin...

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Detalles Bibliográficos
Autores principales: Molt, Robert W., Pellegrini, Erika, Jin, Yi
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6771576/
https://www.ncbi.nlm.nih.gov/pubmed/31038818
http://dx.doi.org/10.1002/chem.201901627
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author Molt, Robert W.
Pellegrini, Erika
Jin, Yi
author_facet Molt, Robert W.
Pellegrini, Erika
Jin, Yi
author_sort Molt, Robert W.
collection PubMed
description Cell signaling by small G proteins uses an ON to OFF signal based on conformational changes following the hydrolysis of GTP to GDP and release of dihydrogen phosphate (P(i)). The catalytic mechanism of GTP hydrolysis by RhoA is strongly accelerated by a GAP protein and is now well defined, but timing of inorganic phosphate release and signal change remains unresolved. We have generated a quaternary complex for RhoA‐GAP‐GDP‐P(i). Its 1.75 Å crystal structure shows geometry for ionic and hydrogen bond coordination of GDP and P(i) in an intermediate state. It enables the selection of a QM core for DFT exploration of a 20 H‐bonded network. This identifies serial locations of the two mobile protons from the original nucleophilic water molecule, showing how they move in three rational steps to form a stable quaternary complex. It also suggests how two additional proton transfer steps can facilitate P(i) release.
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spelling pubmed-67715762019-10-03 A GAP‐GTPase‐GDP‐P(i) Intermediate Crystal Structure Analyzed by DFT Shows GTP Hydrolysis Involves Serial Proton Transfers Molt, Robert W. Pellegrini, Erika Jin, Yi Chemistry Communications Cell signaling by small G proteins uses an ON to OFF signal based on conformational changes following the hydrolysis of GTP to GDP and release of dihydrogen phosphate (P(i)). The catalytic mechanism of GTP hydrolysis by RhoA is strongly accelerated by a GAP protein and is now well defined, but timing of inorganic phosphate release and signal change remains unresolved. We have generated a quaternary complex for RhoA‐GAP‐GDP‐P(i). Its 1.75 Å crystal structure shows geometry for ionic and hydrogen bond coordination of GDP and P(i) in an intermediate state. It enables the selection of a QM core for DFT exploration of a 20 H‐bonded network. This identifies serial locations of the two mobile protons from the original nucleophilic water molecule, showing how they move in three rational steps to form a stable quaternary complex. It also suggests how two additional proton transfer steps can facilitate P(i) release. John Wiley and Sons Inc. 2019-05-27 2019-06-26 /pmc/articles/PMC6771576/ /pubmed/31038818 http://dx.doi.org/10.1002/chem.201901627 Text en © 2019 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
spellingShingle Communications
Molt, Robert W.
Pellegrini, Erika
Jin, Yi
A GAP‐GTPase‐GDP‐P(i) Intermediate Crystal Structure Analyzed by DFT Shows GTP Hydrolysis Involves Serial Proton Transfers
title A GAP‐GTPase‐GDP‐P(i) Intermediate Crystal Structure Analyzed by DFT Shows GTP Hydrolysis Involves Serial Proton Transfers
title_full A GAP‐GTPase‐GDP‐P(i) Intermediate Crystal Structure Analyzed by DFT Shows GTP Hydrolysis Involves Serial Proton Transfers
title_fullStr A GAP‐GTPase‐GDP‐P(i) Intermediate Crystal Structure Analyzed by DFT Shows GTP Hydrolysis Involves Serial Proton Transfers
title_full_unstemmed A GAP‐GTPase‐GDP‐P(i) Intermediate Crystal Structure Analyzed by DFT Shows GTP Hydrolysis Involves Serial Proton Transfers
title_short A GAP‐GTPase‐GDP‐P(i) Intermediate Crystal Structure Analyzed by DFT Shows GTP Hydrolysis Involves Serial Proton Transfers
title_sort gap‐gtpase‐gdp‐p(i) intermediate crystal structure analyzed by dft shows gtp hydrolysis involves serial proton transfers
topic Communications
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6771576/
https://www.ncbi.nlm.nih.gov/pubmed/31038818
http://dx.doi.org/10.1002/chem.201901627
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