19F NMR and DFT analysis reveal structural and electronic transition state features for RhoA-catalyzed GTP hydrolysis

Jin, Yi ORCID: https://orcid.org/0000-0002-6927-4371, Molt Jr, Robert W., Waltho, Jonathan P., Richards, Nigel G. J. ORCID: https://orcid.org/0000-0002-0375-0881 and Blackburn, G. Michael 2016. 19F NMR and DFT analysis reveal structural and electronic transition state features for RhoA-catalyzed GTP hydrolysis. Angewandte Chemie International Edition 55 (10) , pp. 3318-3322. 10.1002/anie.201509477

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Abstract

Molecular details for RhoA/GAP catalysis of the hydrolysis of GTP to GDP are poorly understood. We use 19F NMR chemical shifts in the MgF3− transition state analogue (TSA) complex as a spectroscopic reporter to indicate electron distribution for the γ-PO3− oxygens in the corresponding TS, implying that oxygen coordinated to Mg has the greatest electron density. This was validated by QM calculations giving a picture of the electronic properties of the transition state (TS) for nucleophilic attack of water on the γ-PO3− group based on the structure of a RhoA/GAP-GDP-MgF3− TSA complex. The TS model displays a network of 20 hydrogen bonds, including the GAP Arg85′ side chain, but neither phosphate torsional strain nor general base catalysis is evident. The nucleophilic water occupies a reactive location different from that in multiple ground state complexes, arising from reorientation of the Gln-63 carboxamide by Arg85′ to preclude direct hydrogen bonding from water to the target γ-PO3− group.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Chemistry
Subjects:	Q Science > QD Chemistry
Uncontrolled Keywords:	19F NMR; enzyme catalysis; GTP hydrolases; phosphoryl transfer; reaction mechanisms
Publisher:	Wiley
ISSN:	1433-7851
Date of First Compliant Deposit:	1 April 2016
Date of Acceptance:	20 January 2016
Last Modified:	06 Jan 2024 02:24
URI:	https://orca.cardiff.ac.uk/id/eprint/88540

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