Journal article
A structural and mechanistic study of π-clamp-mediated cysteine perfluoroarylation
Scientific reports, Vol.7(1), pp.7954-11
08/11/2017
DOI: 10.1038/s41598-017-08402-2
PMCID: PMC5554146
PMID: 28801573
Abstract
Natural enzymes use local environments to tune the reactivity of amino acid side chains. In searching for small peptides with similar properties, we discovered a four-residue π-clamp motif (Phe-Cys-Pro-Phe) for regio- and chemoselective arylation of cysteine in ribosomally produced proteins. Here we report mutational, computational, and structural findings directed toward elucidating the molecular factors that drive π-clamp-mediated arylation. We show the significance of a trans conformation prolyl amide bond for the π-clamp reactivity. The π-clamp cysteine arylation reaction enthalpy of activation (ΔH ) is significantly lower than a non-π-clamp cysteine. Solid-state NMR chemical shifts indicate the prolyl amide bond in the π-clamp motif adopts a 1:1 ratio of the cis and trans conformation, while in the reaction product Pro3 was exclusively in trans. In two structural models of the perfluoroarylated product, distinct interactions at 4.7 Å between Phe1 side chain and perfluoroaryl electrophile moiety are observed. Further, solution F NMR and isothermal titration calorimetry measurements suggest interactions between hydrophobic side chains in a π-clamp mutant and the perfluoroaryl probe. These studies led us to design a π-clamp mutant with an 85-fold rate enhancement. These findings will guide us toward the discovery of small reactive peptides to facilitate abiotic chemistry in water.
Details
- Title: Subtitle
- A structural and mechanistic study of π-clamp-mediated cysteine perfluoroarylation
- Creators
- Peng Dai - Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, United StatesJonathan K Williams - Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, United StatesChi Zhang - Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, United StatesMatthew Welborn - Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, United StatesJames J Shepherd - Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, United StatesTianyu Zhu - Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, United StatesTroy Van Voorhis - Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, United StatesMei Hong - Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, United StatesBradley L Pentelute - Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, United States. blp@mit.edu
- Resource Type
- Journal article
- Publication Details
- Scientific reports, Vol.7(1), pp.7954-11
- DOI
- 10.1038/s41598-017-08402-2
- PMID
- 28801573
- PMCID
- PMC5554146
- NLM abbreviation
- Sci Rep
- ISSN
- 2045-2322
- eISSN
- 2045-2322
- Publisher
- England
- Grant note
- R01 GM088204 / NIGMS NIH HHS R01 GM110535 / NIGMS NIH HHS
- Language
- English
- Date published
- 08/11/2017
- Academic Unit
- Chemistry
- Record Identifier
- 9983985864802771
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