36578-01-5Relevant articles and documents
Discovery, characterization and engineering of ligases for amide synthesis
Winn, Michael,Rowlinson, Michael,Wang, Fanghua,Bering, Luis,Francis, Daniel,Levy, Colin,Micklefield, Jason
, p. 391 - 398 (2021/05/28)
Coronatine and related bacterial phytotoxins are mimics of the hormone jasmonyl-l-isoleucine (JA-Ile), which mediates physiologically important plant signalling pathways1–4. Coronatine-like phytotoxins disrupt these essential pathways and have potential in the development of safer, more selective herbicides. Although the biosynthesis of coronatine has been investigated previously, the nature of the enzyme that catalyses the crucial coupling of coronafacic acid to amino acids remains unknown1,2. Here we characterize a family of enzymes, coronafacic acid ligases (CfaLs), and resolve their structures. We found that CfaL can also produce JA-Ile, despite low similarity with the Jar1 enzyme that is responsible for ligation of JA and l-Ile in plants5. This suggests that Jar1 and CfaL evolved independently to catalyse similar reactions—Jar1 producing a compound essential for plant development4,5, and the bacterial ligases producing analogues toxic to plants. We further demonstrate how CfaL enzymes can be used to synthesize a diverse array of amides, obviating the need for protecting groups. Highly selective kinetic resolutions of racemic donor or acceptor substrates were achieved, affording homochiral products. We also used structure-guided mutagenesis to engineer improved CfaL variants. Together, these results show that CfaLs can deliver a wide range of amides for agrochemical, pharmaceutical and other applications.
Formation of Non-Natural α,α-Disubstituted Amino Esters via Catalytic Michael Addition
Teegardin, Kip A.,Gotcher, Lacey,Weaver, Jimmie D.
supporting information, p. 7239 - 7244 (2018/11/25)
The enolate monoanion of amino esters is explored, and the first catalytic Michael addition of α-amino esters is demonstrated. These studies indicate that the acidity of the αC-H is the primary factor determining reactivity. Thus, polyfluorophenylglycine amino esters yield novel α-amino esters in the presence of a catalytic amount of a guanidine-derived base and Michael acceptors. Reactivity requires an acidic N-H, which is accomplished using common protecting groups such as N-Bz, N-Boc, and N-Cbz. Calculations and labeling experiments provide insight into the governing principles in which a key C-to-N proton transfer occurs, resulting in an expansion of the scope to include a number of natural amino esters. The study culminates with a late-stage functionalization of peptidic γ-secretase inhibitor, DAPT.
Isotope-labeled differential profiling of metabolites using N-benzoyloxysuccinimide derivatization coupled to liquid chromatography/high-resolution tandem mass spectrometry
Wagner, Michel,Ohlund, Leanne B.,Shiao, Tze Chieh,Vézina, Amélie,Annabi, Borhane,Roy, René,Sleno, Lekha
, p. 1632 - 1640 (2015/11/16)
Rationale An isotopic labeling strategy based on derivatizing amine-containing metabolites has been developed using light (12C6) and heavy (13C6) N-benzoyloxysuccinimide reagents for semi-targeted metabolomic applications. Methods Differentially labeled samples were combined and analyzed simultaneously by liquid chromatography/high-resolution tandem mass spectrometry (LC/HR-MS/MS) to compare relative amounts of amine-containing metabolites. The selectivity of the reaction was determined with model metabolites and was shown to also be applicable to thiol and phenol moieties. The potential for relative quantitation was evaluated in cell extracts and the method was then applied to quantify metabolic perturbations occurring in human cultured cells under normal vs. oxidative stress conditions. Results A total of 279 derivatized features were detected in HL60 cell extracts, 77 of which yielded significant concentration changes upon oxidative stress treatment. Based on accurate mass measurements and MS/MS spectral matching with reference standard solutions, 10 metabolites were clearly identified. Derivatized compounds were found to have diagnostic fragment ions from the reagent itself, as well as structurally informative ions useful for metabolite identification. Conclusions This simple derivatization reaction can be applied to the relative quantitation of amine-, thiol- and phenol-containing compounds, with improved sensitivity and chromatographic peak shapes due to the increased hydrophobicity of polar metabolites not readily amenable to reversed-phase LC/MS analysis.
