The University of Southampton
University of Southampton Institutional Repository

A front-face 'SNi synthase' engineered from a retaining 'double-SN2' hydrolase

A front-face 'SNi synthase' engineered from a retaining 'double-SN2' hydrolase
A front-face 'SNi synthase' engineered from a retaining 'double-SN2' hydrolase
SNi-like mechanisms, which involve front-face leaving group departure and nucleophile approach, have been observed experimentally and computationally in chemical and enzymatic substitution at α-glycosyl electrophiles. Since SNi-like, SN1 and SN2 substitution pathways can be energetically comparable, engineered switching could be feasible. Here, engineering of Sulfolobus solfataricus β-glycosidase, which originally catalyzed double SN2 substitution, changed its mode to SNi-like. Destruction of the first SN2 nucleophile through E387Y mutation created a β-stereoselective catalyst for glycoside synthesis from activated substrates, despite lacking a nucleophile. The pH profile, kinetic and mutational analyses, mechanism-based inactivators, X-ray structure and subsequent metadynamics simulations together suggest recruitment of substrates by π–sugar interaction and reveal a quantum mechanics–molecular mechanics (QM/MM) free-energy landscape for the substitution reaction that is similar to those of natural, SNi-like glycosyltransferases. This observation of a front-face mechanism in a β-glycosyltransfer enzyme highlights that SNi-like pathways may be engineered in catalysts with suitable environments and suggests that 'β-SNi' mechanisms may be feasible for natural glycosyltransfer enzymes.
1552-4450
874-881
Iglesias-Fernandez, Javier
df84d383-3410-4a5c-8916-7fe67f194c9c
Hancock, Susan M.
340716ea-a96e-4de4-967b-f012109410ba
Lee, Seung Seo
ee34fa26-5fb6-48c8-80c2-1f13ec4ccceb
Khan, Maola
52255adc-628e-440c-ae9e-0235b184f76d
Kirkpatrick, Jo
3740b8ad-dd4e-443c-bac3-3e1958364d13
Oldham, Neil J.
dc789397-aee5-48be-b329-5875b3cb54d4
McAuley, Katherine
b49edb51-706a-47b7-8aeb-5e7ba3321fcc
Fordham-Skelton, Anthony
2710ef20-8de0-4ccc-8adf-c6e620dab790
Rovira, Carme
22dc3744-cd39-4647-be77-36e308f10ca1
Davis, Benjamin G.
ef72f03a-30d1-4724-8eb4-6a5b5db17aa6
Iglesias-Fernandez, Javier
df84d383-3410-4a5c-8916-7fe67f194c9c
Hancock, Susan M.
340716ea-a96e-4de4-967b-f012109410ba
Lee, Seung Seo
ee34fa26-5fb6-48c8-80c2-1f13ec4ccceb
Khan, Maola
52255adc-628e-440c-ae9e-0235b184f76d
Kirkpatrick, Jo
3740b8ad-dd4e-443c-bac3-3e1958364d13
Oldham, Neil J.
dc789397-aee5-48be-b329-5875b3cb54d4
McAuley, Katherine
b49edb51-706a-47b7-8aeb-5e7ba3321fcc
Fordham-Skelton, Anthony
2710ef20-8de0-4ccc-8adf-c6e620dab790
Rovira, Carme
22dc3744-cd39-4647-be77-36e308f10ca1
Davis, Benjamin G.
ef72f03a-30d1-4724-8eb4-6a5b5db17aa6

Iglesias-Fernandez, Javier, Hancock, Susan M., Lee, Seung Seo, Khan, Maola, Kirkpatrick, Jo, Oldham, Neil J., McAuley, Katherine, Fordham-Skelton, Anthony, Rovira, Carme and Davis, Benjamin G. (2017) A front-face 'SNi synthase' engineered from a retaining 'double-SN2' hydrolase. Nature Chemical Biology, 13, 874-881. (doi:10.1038/nchembio.2394).

Record type: Article

Abstract

SNi-like mechanisms, which involve front-face leaving group departure and nucleophile approach, have been observed experimentally and computationally in chemical and enzymatic substitution at α-glycosyl electrophiles. Since SNi-like, SN1 and SN2 substitution pathways can be energetically comparable, engineered switching could be feasible. Here, engineering of Sulfolobus solfataricus β-glycosidase, which originally catalyzed double SN2 substitution, changed its mode to SNi-like. Destruction of the first SN2 nucleophile through E387Y mutation created a β-stereoselective catalyst for glycoside synthesis from activated substrates, despite lacking a nucleophile. The pH profile, kinetic and mutational analyses, mechanism-based inactivators, X-ray structure and subsequent metadynamics simulations together suggest recruitment of substrates by π–sugar interaction and reveal a quantum mechanics–molecular mechanics (QM/MM) free-energy landscape for the substitution reaction that is similar to those of natural, SNi-like glycosyltransferases. This observation of a front-face mechanism in a β-glycosyltransfer enzyme highlights that SNi-like pathways may be engineered in catalysts with suitable environments and suggests that 'β-SNi' mechanisms may be feasible for natural glycosyltransfer enzymes.

Text
Accepted-manuscript - Accepted Manuscript
Download (11MB)

More information

Accepted/In Press date: 8 March 2017
e-pub ahead of print date: 12 June 2017
Published date: August 2017
Organisations: CBDT

Identifiers

Local EPrints ID: 408707
URI: http://eprints.soton.ac.uk/id/eprint/408707
ISSN: 1552-4450
PURE UUID: e7f56d42-3ce9-4908-acd4-9bb547f5e8cf
ORCID for Seung Seo Lee: ORCID iD orcid.org/0000-0002-8598-3303

Catalogue record

Date deposited: 26 May 2017 04:03
Last modified: 16 Mar 2024 05:14

Export record

Altmetrics

Contributors

Author: Javier Iglesias-Fernandez
Author: Susan M. Hancock
Author: Seung Seo Lee ORCID iD
Author: Maola Khan
Author: Jo Kirkpatrick
Author: Neil J. Oldham
Author: Katherine McAuley
Author: Anthony Fordham-Skelton
Author: Carme Rovira
Author: Benjamin G. Davis

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×