A GAP-GTPase-GDP-Pi intermediate crystal structure analyzed by DFT shows GTP hydrolysis involves serial proton transfers

Molt, Robert W., Pellegrini, Erika and Jin, Yi ORCID: https://orcid.org/0000-0002-6927-4371 2019. A GAP-GTPase-GDP-Pi intermediate crystal structure analyzed by DFT shows GTP hydrolysis involves serial proton transfers. Chemistry - A European Journal 25 (36) , pp. 8484-8488. 10.1002/chem.201901627

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Abstract

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 (Pi). 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‐Pi. Its 1.75 Å crystal structure shows geometry for ionic and hydrogen bond coordination of GDP and Pi 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 Pi release.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Chemistry
Publisher:	Wiley
ISSN:	0947-6539
Funders:	Wellcome Trust
Date of First Compliant Deposit:	2 July 2019
Date of Acceptance:	30 April 2019
Last Modified:	06 Jan 2024 02:24
URI:	https://orca.cardiff.ac.uk/id/eprint/123904

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