Evaluation of fluoropyruvate as nucleophile in reactions catalysed by N-acetyl neuraminic acid lyase variants: scope, limitations and stereoselectivity
“…Fitting to a Michaelis-Menten kinetic model provided a K M of 3.2 AE 0.1 mM, a V max of 40.0 AE 0.2 lmolÁmin À1 Ámg À1 , and a k cat of 22.1 AE 0.1 s À1 . These values are consistent with the kinetic parameters obtained for other N-acetylneuraminate lyase enzymes in the literature [15,22,[41][42][43].…”
N-Acetylneuraminate lyase is the first committed enzyme in the degradation of sialic acid by bacterial pathogens. In this study, we analyzed the kinetic parameters of N-acetylneuraminate lyase from methicillin-resistant Staphylococcus aureus (MRSA). We determined that the enzyme has a relatively high K of 3.2 mm, suggesting that flux through the catabolic pathway is likely to be controlled by this enzyme. Our data indicate that sialic acid alditol, a known inhibitor of N-acetylneuraminate lyase enzymes, is a stronger inhibitor of MRSA N-acetylneuraminate lyase than of Clostridium perfringens N-acetylneuraminate lyase. Our analysis of the crystal structure of ligand-free and 2R-sialic acid alditol-bound MRSA N-acetylneuraminate lyase suggests that subtle dynamic differences in solution and/or altered binding interactions within the active site may account for species-specific inhibition.
“…Fitting to a Michaelis-Menten kinetic model provided a K M of 3.2 AE 0.1 mM, a V max of 40.0 AE 0.2 lmolÁmin À1 Ámg À1 , and a k cat of 22.1 AE 0.1 s À1 . These values are consistent with the kinetic parameters obtained for other N-acetylneuraminate lyase enzymes in the literature [15,22,[41][42][43].…”
N-Acetylneuraminate lyase is the first committed enzyme in the degradation of sialic acid by bacterial pathogens. In this study, we analyzed the kinetic parameters of N-acetylneuraminate lyase from methicillin-resistant Staphylococcus aureus (MRSA). We determined that the enzyme has a relatively high K of 3.2 mm, suggesting that flux through the catabolic pathway is likely to be controlled by this enzyme. Our data indicate that sialic acid alditol, a known inhibitor of N-acetylneuraminate lyase enzymes, is a stronger inhibitor of MRSA N-acetylneuraminate lyase than of Clostridium perfringens N-acetylneuraminate lyase. Our analysis of the crystal structure of ligand-free and 2R-sialic acid alditol-bound MRSA N-acetylneuraminate lyase suggests that subtle dynamic differences in solution and/or altered binding interactions within the active site may account for species-specific inhibition.
“…Aldol addition of 6 a to aldehydes mediated by pyruvate aldolases is the methodology of choice for the straightforward synthesis of 4‐hydroxy‐2‐keto acids. Class I 6 a ‐dependent aldolases, for example, NeuA (EC 4.1.3.3) and its variants are highly specific for 6 a , tolerating only fluoropyruvate as an alternative nucleophile …”
Section: Methodsmentioning
confidence: 99%
“…Class I 6a-dependent aldolases, for example, NeuA (EC 4.1.3.3)a nd its variantsa re highly specific for 6a,t olerating only fluoropyruvate as an alternative nucleophile. [6,11,28] The class I trans-o-hydroxybenzylidene pyruvate hydratasealdolase( HBPA; EC 4.1.2.45) was found to accept fluoropyruvate as an ucleophile with high efficiency,d iastereoselectivity, and enantioselectivity. [29] In vivo, this enzyme participates in the degradation pathways of naphthalene and naphthalene sulfonates in bacteria by catalyzing the reversible aldol addition of 6a to salicylaldehydea nd subsequentd ehydration.…”
The asymmetric aldol addition reaction mediated by aldolases is recognized as a green and sustainable method for carbon-carbon bond formation. Research in this area has unveiled their unprecedented synthetic potential toward diverse, new chemical structures; novel product families; and even as a technology for industrial manufacturing processes. Despite these advances, aldolases have long been regarded as strictly selective catalysts, particularly for nucleophilic substrates, which limits their broad applicability. In recent years, advances in screening technologies and metagenomics have uncovered novel C-C biocatalysts from superfamilies of widely known lyases. Moreover, protein engineering has revealed the extraordinary malleability of different carboligases to offer a toolbox of biocatalysts active towards a large structural diversity of nucleophile substrates. Herein, the nucleophile ambiguity of native and engineered aldolases is discussed with recent examples to prove this novel concept.
“…[12,15] TheC lass I( lysine-dependent) aldolase, N-acetyl neuraminic acid lyase (NAL), has been shown to accept fluoropyruvate as an alternative donor substrate to pyruvate. [16] The value of NALi nt he synthesis of fluorinated products is, however, limited by poor stereocontrol and narrow demonstrated substrate scope.M oreover,N AL accepts only polyhydroxylated substrates which often yield products as complex anomeric mixtures of both pyranose and furanose forms. We therefore sought another Class Ialdolase that would also accept fluoropyruvate as adonor, but would have more value in the synthesis of building blocks [17] for drug discovery.…”
The trans-o-hydroxybenzylidene pyruvate aldolasecatalysed reactions between fluoropyruvate and many (hetero)aromatic aldehydes yield aldol adducts without subsequent dehydration. Treatment of the reaction products with hydrogen peroxide yields the corresponding syn-configured afluoro b-hydroxy carboxylic acids which have > 98 %ee. The overall chemoenzymatic approach,i nw hich fluoropyruvate serves as af luoroacetate equivalent, may be exploited in the synthesis of polar building blocks and fragments with potential value in drug discovery.Fluorination can profoundly affect the conformation, bioavailability,m etabolism, pharmacokinetics and pharmacodynamics of bioactive small molecules.[1] Thei ntroduction of fluorine is therefore widely used to tune biological function, and around 20 %ofleading drugs contain at least one fluorine atom [2] (10 of the top 50 drugs in 2013 by US prescription [3] ). Examples of leading fluorinated pharmaceuticals include the cholesterol-lowering drug Rosuvastatin [4] and the antidiabetic drug Sitagliptin. [4] Thec ontrolled formation of fluorine-substituted stereocentres,h owever, presents as ignificant challenge.M ost usually,t he challenge is addressed by stereoselective CÀF bond formation. Fore xample,t he fluorination of allylic silanes is often diastereoselective, [5] and organo- [6] and Pd- [7] catalysed methods enable the enantioselective a-fluorination of carbonyl compounds. Stereoselective CÀCbond formation could provide acomplementary approach for controlling fluorine-bearing stereocentres (Scheme 1). However,aldol (and related) reactions of esters of fluoroacetic acid generally exhibit poor diastereoselectivity (e.g.r eactions of lithium enolates, [8] Reformatsky reactions [9] and Mukayama aldol reactions [10]
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