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Synthesis of C -glycoside analogues of isopropyl β-D-1-thiogalactopyranoside (IPTG) and 1-β-D-galactopyranosyl-2-methylpropane. Conformational analysis and evaluation as inhibitors of the lac repressor in E. coli and as galactosidase inhibitors.
- Source :
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Organic & biomolecular chemistry [Org Biomol Chem] 2024 Sep 18; Vol. 22 (36), pp. 7460-7477. Date of Electronic Publication: 2024 Sep 18. - Publication Year :
- 2024
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Abstract
- Isopropyl 1-thio-β-D-galactopyranoside (IPTG, 1) is used widely as an inducer of protein expression in E. coli and 1-β-D-galactopyranosyl-2-methylpropane (2), a C -glycoside analogue of 1, has also been identified as an inducer. Here, synthesis and study of mimetics of 1 and 2, 1-β-D-galactopyranosyl-2-methylpropan-1-ols and two cyclic acetals derivatives, that constrain the presentation of the iPr group in various geometries is described. Conformational analysis of C -glycosides in protic solvent is performed using (i) Desmond metadynamics simulations (OPLS4) and (ii) use of <superscript>3</superscript> J <subscript>HH</subscript> values obtained by <superscript>1</superscript> H-NMR spectroscopy. 1-β-D-Galactopyranosyl-2-methylpropane (2) is an effective protein expression inducer when compared to the new mimetics, which were less effective or did not induce expression. 1-β-D-Galactopyranosyl-2-methylpropane (2) led to significantly reduced proteolysis during protein expression, compared to IPTG suggesting that recombinant protein purification will be easier to achieve with 2, yielding proteins with higher quality and activity. IPTG reduced bacterial growth to a greater degree than 2 compared to the control. IPTG's isopropyl group was observed by molecular dynamics (MD) simulations to be flexible in the binding pocket, deviating from its crystal structure binding mode, without impacting other interactions. The MD simulations predicted that 1-β-D-galactopyranosyl-2-methylpropane (2) was more likely than IPTG to bind the repressor with a conformation favoured in protic solvent, while maintaining interactions observed for IPTG. MD simulations predicted that isobutanol derivatives may disrupt interactions associated with IPTG's binding mode. The compounds were also evaluated as inhibitors of galactosidases, with 2 being the more potent inhibitor of the E. coli β-galactosidase. The constrained cyclic acetals showed similar inhibition constants to IPTG indicating E. coli β-galactosidase can recognize galactopyranoses with varying presentation of the iPr group.
- Subjects :
- Molecular Conformation
beta-Galactosidase antagonists & inhibitors
beta-Galactosidase metabolism
Escherichia coli drug effects
Escherichia coli metabolism
Glycosides chemistry
Glycosides pharmacology
Glycosides chemical synthesis
Isopropyl Thiogalactoside pharmacology
Enzyme Inhibitors pharmacology
Enzyme Inhibitors chemistry
Enzyme Inhibitors chemical synthesis
Subjects
Details
- Language :
- English
- ISSN :
- 1477-0539
- Volume :
- 22
- Issue :
- 36
- Database :
- MEDLINE
- Journal :
- Organic & biomolecular chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 39189157
- Full Text :
- https://doi.org/10.1039/d4ob01286k