First access to a mycolic acid-based bioorthogonal reporter for the study of the mycomembrane and mycoloyltransferases in Corynebacteria

Abstract

In this study we describe the first synthesis of an alkyne-based trehalose monomycolate probe closely mimicking the complex pattern of mycolic acids and its utility for the study of mycomembrane and mycoloyltransferases in Corynebacteria.

Chemical Reporters for Bacterial Glycans: Development and Applications

“…In addition to the simplified linear-chain TMM derivatives, in 2019, the Bourdreux and Guianvarc'h groups reported an O-linked TMM derivative bearing an alkynemodified mycolate chain with the native α-branch and βhydroxy group included, here named O-AlkTMM-C23 (115, Figure 38C). 273 Once the challenging stereoselective synthesis of the native mycolic acid building block was completed, it was coupled to trehalose using the same monoesterification method shown in Figure 39A. 273 Compound 115 was shown to efficiently incorporate into the cell surface of C. glutamicum.…”

“…273 Once the challenging stereoselective synthesis of the native mycolic acid building block was completed, it was coupled to trehalose using the same monoesterification method shown in Figure 39A. 273 Compound 115 was shown to efficiently incorporate into the cell surface of C. glutamicum. 273 Such compounds may be instrumental in teasing apart the structural features of mycolate glycolipids that confer efficient and specific processing by mycoloyltransferase/hydrolase enzymes.…”

Metabolic Labeling of Bacterial Glycans

“…an acyl chain with a β-hydroxyl and an α-lipidic chain in an anti configuration. 110 The synthesis started from a β-keto ester bearing a terminal alkyne group, and involved as key steps a Noyori enantioselective reduction and an anti-selective alkylation in order to introduce both the hydroxyl and the α-chain in an anti relationship, mimicking the native structure of mycolic acids (Scheme 14).…”

“…To this end, Bourdreux and Guianvarc'h developed alkyne-based TMM probes including either a simple β-hydroxylated fatty acid chain which is a hallmark of the natural meromycolate chain Alkm 13 α 0 TMM or an extra α-branched chain similar to those of mycolic acids and most closely mimicking TMM, Alkm 13 α 10 TMM. 110 This latter demonstrated its utility to label mycomembrane with a short labeling time and very low doses in C. glutamicum and to study mycoloyltransferases in vitro since the mycolic acid analogs based-probe most closely mimicking TMM, Alkm 13 α 10 TMM, showed different behavior in comparison with the unbranched lipid-trehalose probe.…”

Synthesis of chemical tools to label the mycomembrane of corynebacteria using modified iron(iii) chloride-mediated protection of trehalose

“…27 Recently, we described the first alkyne-modified trehalose monomycolate probes closely mimicking the native TMM Alkm 13 α 0 TMM and Alkm 13 α 10 TMM, including either a simple β-hydroxylated fatty acid chain, which is a hallmark of the natural meromycolate chain, or an extra α-branched chain similar to those of mycolic acids that allows more efficient processing by mycoloyltransferases. 28 In a recent work, Kiessling's group developed a quencher-trehalose-fluorophore QTF probe with an alkyl chain bearing the fluorescent dye Bodipy fluorophore and the fluorescence quencher Dabcyl linked to the 6′hydroxyl of trehalose. 29 This elegant strategy was then also used by Swarts et al with another di-O-acylated trehalose FRET-TDM.…”