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Do Electrostatic Interactions with Positively Charged Active Site Groups Tighten the Transition State for Enzymatic Phosphoryl Transfer?

Nikolic-Hughes, Ivana and Rees, Douglas C. and Herschlag, Daniel (2004) Do Electrostatic Interactions with Positively Charged Active Site Groups Tighten the Transition State for Enzymatic Phosphoryl Transfer? Journal of the American Chemical Society, 126 (38). pp. 11814-11819. ISSN 0002-7863. doi:10.1021/ja0480421. https://resolver.caltech.edu/CaltechAUTHORS:20141212-144814941

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Abstract

The effect of electrostatic interactions on the transition-state character for enzymatic phosphoryl transfer has been a subject of much debate. In this work, we investigate the transition state for alkaline phosphatase (AP) using linear free-energy relationships (LFERs). We determined kcat/KM for a series of aryl sulfate ester monoanions to obtain the Brønsted coefficient, βlg, and compared the value to that obtained previously for a series of aryl phosphorothioate ester dianion substrates. Despite the difference in substrate charge, the observed Brønsted coefficients for AP-catalyzed aryl sulfate and aryl phosphorothioate hydrolysis (−0.76 ± 0.14 and −0.77 ± 0.10, respectively) are strikingly similar, with steric effects being responsible for the uncertainties in these values. Aryl sulfates and aryl phosphates react via similar loose transition states in solution. These observations suggest an apparent equivalency of the transition states for phosphorothioate and sulfate hydrolysis reactions at the AP active site and, thus, negligible effects of active site electrostatic interactions on charge distribution in the transition state.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1021/ja0480421DOIArticle
http://pubs.acs.org/doi/abs/10.1021/ja0480421PublisherArticle
ORCID:
AuthorORCID
Rees, Douglas C.0000-0003-4073-1185
Contact Email Address:phoebe@caltech.edu
Additional Information:Copyright © 2004 American Chemical Society. Received April 5, 2004. We are grateful to P. Dervan for generously sharing laboratory space and equipment for the aryl sulfate syntheses, A. Heckel and P. Arora for synthetic advice, J. Zalatan for helpful discussions, P. O'Brien and members of the Herschlag and Rees labs for comments on the manuscript. This work was funded by grants from the NIH to D.H. (GM64798) and D.C.R. (GM45162). I.N-H. is an AHA Predoctoral Fellow.
Funders:
Funding AgencyGrant Number
NIHGM64798
NIHGM45162
American Heart Association (AHA) Predoctoral FellowshipUNSPECIFIED
Issue or Number:38
DOI:10.1021/ja0480421
Record Number:CaltechAUTHORS:20141212-144814941
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20141212-144814941
Official Citation:Do Electrostatic Interactions with Positively Charged Active Site Groups Tighten the Transition State for Enzymatic Phosphoryl Transfer? Ivana Nikolic-Hughes, Douglas C. Rees, and Daniel Herschlag Journal of the American Chemical Society 2004 126 (38), 11814-11819
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:52783
Collection:CaltechAUTHORS
Deposited By: SWORD User
Deposited On:22 Dec 2014 21:06
Last Modified:10 Nov 2021 19:43

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