- Discovery, characterization and engineering of ligases for amide synthesis
-
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.
- Winn, Michael,Rowlinson, Michael,Wang, Fanghua,Bering, Luis,Francis, Daniel,Levy, Colin,Micklefield, Jason
-
p. 391 - 398
(2021/05/28)
-
- GRANZYME B DIRECTED IMAGING AND THERAPY
-
Provided herein are heterocyclic compounds useful for imaging Granzyme B. Methods of imaging Granzyme B, combination therapies, and kits comprising the Granzyme B imaging agents are also provided.
- -
-
Page/Page column 135; 140
(2019/09/04)
-
- Formation of Non-Natural α,α-Disubstituted Amino Esters via Catalytic Michael Addition
-
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.
- Teegardin, Kip A.,Gotcher, Lacey,Weaver, Jimmie D.
-
supporting information
p. 7239 - 7244
(2018/11/25)
-
- NMR-based assignment of isoleucine: Vs. allo -isoleucine stereochemistry
-
A simple 1H and 13C NMR spectrometric analysis is demonstrated that permits differentiation of isoleucine and allo-isoleucine residues by inspection of the chemical shift and coupling constants of the signals associated with the proton and carbon at the α-stereocentre. This is applied to the estimation of epimerisation during metal-free N-arylation and peptide coupling reactions.
- Anderson, Zoe J.,Hobson, Christian,Needley, Rebecca,Song, Lijiang,Perryman, Michael S.,Kerby, Paul,Fox, David J.
-
p. 9372 - 9378
(2017/11/22)
-
- Isotope-labeled differential profiling of metabolites using N-benzoyloxysuccinimide derivatization coupled to liquid chromatography/high-resolution tandem mass spectrometry
-
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.
- Wagner, Michel,Ohlund, Leanne B.,Shiao, Tze Chieh,Vézina, Amélie,Annabi, Borhane,Roy, René,Sleno, Lekha
-
p. 1632 - 1640
(2015/11/16)
-
- Synthesis, characterization, and cytotoxicity of mixed-ligand complexes of palladium(II) with 1,10-phenanthroline and N-carbonyl-L-isoleucine dianion 1
-
Three novel palladium(II) complexes [Pd(Phen)(Bzile)] (I), [Pd(Phen)(p-mBzile)] (II), and [Pd(Phen)(p-NBzile)]·H2O (III), where Bzile = N-benzoyl-L-isolecine), p-MBzile = N-(p-methylbenzoyl)-L- isolecine), p-NBzile = N-(p-nitrobenzoyl)-L-isolec
- Zhang,Wang,Liu,Zhang,Du,Li,Wang,Li,Zhou
-
p. 115 - 119
(2014/03/21)
-
- One-pot preparation of oxazol-5(4H)-ones from amino acids in aqueous solvents
-
A method for one-pot synthesis of oxazol-5(4H)-ones has been developed using 4-(4,6-dimethoxy-l,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMT-MM), which is available for the activation of carboxylic acids in an aqueous solvent. The oxazolones were prepared by the TV-acylation of amino acids with carboxylic acids and the subsequent cyclodehydration of the resulting N-acylamino acids by the addition of N,N-diethylaniline. Since both these reactions proceed effectively with the same coupling reagent, DMT-MM, in aqueous solvents, the procedure is simplified and becomes easy to perform. In addition, 5-(triazinyloxy)oxazole derivatives have been synthesized by controlling the basicity of the reaction system.
- Fujita, Hikaru,Kunishima, Munetaka
-
p. 907 - 912
(2012/08/08)
-
- A new method proposed for the determination of absolute configurations of α-amino acids
-
Enantiopure α-amino acids were converted to 4-substituted 2-aryl- and 2-alkyl-5(4H)-oxazolones under partial racemization. These nonracemic mixtures were dissolved in CDCl3, an equimolar amount of the chiral dirhodium complex Rh2(II)[(R)-(+)-MTPA]4 (MTPA-H = Mosher's acid) was added, and the 1H NMR spectra of the resulting samples were recorded [dirhodium method). The relative intensities of 1H signals dispersed by the formation of diastereomeric adducts allow to determine the absolute configuration (AC) of the starting a-amino acids. Binding atoms in the adducts were identified by comparing the 1H and 13C chemical shifts of the oxazolones in the absence and presence of Rh2(II)[(R)-(+)- MTPA]4. Thereby, information about the scope and limits of this method can be extracted. A protocol how to use this method is presented. Copyright
- Gomez, Edison Diaz,Duddeck, Helmut
-
experimental part
p. 222 - 227
(2010/02/28)
-
- Preparation of N-acyl derivatives of amino acids from acyl chlorides and amino acids in the presence of cationic surfactants. A variation of the Schotten-Baumann method of benzoylation of amino acids
-
A very efficient method for the preparation of N-acylamino acids from the corresponding acyl chloride and amino acid is described. Amino acids, potassium carbonate, acyl chloride, and a catalytic amount of cationic surfactants were mixed in tetrahydrofuran and refluxed without ever obtaining a clear reaction mixture. After hot filtration, the product was isolated from the hot tetrahydrofuran solution in very high or almost quantitative yields.
- Jursic,Neumann
-
p. 555 - 564
(2007/10/03)
-
- Reactivity of the Amino Groups of α-Amino Acids and Dipeptides in Reaction with Benzoyl Chloride in a Dioxane-Water Solvent
-
The kinetic characteristics (rate constants, activation energies, and entropies of activation) for the reaction of a series of α-amino acids and dipeptides with benzoyl chloride in aqueous dioxane are presented.The amino group in the investigated α-amino acids has high reactivity 4 liter/mole*sec>; the dipeptides have lower reactivity 3 liter/mole*sec>.
- Kuritsyn, L. V.,Kalinina, N. V.
-
p. 767 - 770
(2007/10/02)
-
