Synthetic esters recognized by glucuronoyl esterase from Schizophyllum commune

Abstract

Glucuronoyl esterase is a novel carbohydrate esterase recently discovered in the cellulolytic system of the wood-rotting fungus Schizophyllum commune on the basis of its ability to hydrolyze methyl ester of 4-O-methyl-D-glucuronic acid. This substrate was not fully corresponding to the anticipated function of the enzyme to hydrolyze esters between xylan-bound 4-O-methyl-D-glucuronic acid and lignin alcohols occurring in plant cell walls. In this work we showed that the enzyme was capable of hydrolyzing two synthetic compounds that mimic the ester linkages described in lignin-carbohydrate complexes, esters of 4-O-methyl-D-glucuronic and D-glucuronic acid with 3-(4-methoxyphenyl)propyl alcohol. A comparison of kinetics of hydrolysis of methyl and 3-(4-methoxyphenyl)propyl esters indicated that the glucuronoyl esterase recognizes the uronic acid part of the substrates better than the alcohol type. The catalytic efficiency of the enzyme was much higher with the ester of 4-O-methyl-D-glucuronic acid than with that of D-glucuronic acid. Examination of the action of glucuronoyl esterase on a series of methyl esters of 4-O-methyl-D-glucopyranuronosyl residues alpha-1,2-linked to xylose and several xylooligosaccharides suggested that the rate of deesterification is independent of the character of the carbohydrate part glycosylated by the 4-O-methyl-D-glucuronic acid.

Characterisation of three fungal glucuronoyl esterases on glucuronic acid ester model compounds

“…Most studies of GEs to date have been conducted using synthetic substrates obtained through organic synthesis (Biely et al 2015; D’Errico et al 2015; Ďuranová et al 2009a; Katsimpouras et al 2014; Li et al 2007; Špániková et al 2007). The production of these compounds is laborious and requires expertise in organic chemistry, and the compounds often do not allow for high-throughput screening due to their requirement for HPLC or NMR analyses.…”

“…In the aryl esters, R 1 and R glycosidic have so far been limited to hydrogens and methyl groups. In addition, structures with methyl esters of 4-O-methyl- d -glucuronic acid α1-2-linked to xylose units have been used (Špániková et al 2007). Of the many synthetic substrates used for GE assays, only a few are commercially available; benzyl- d -glucuronic acid (BnGlcA), allyl- d -glucuronic acid (allylGlcA) and methyl- d -glucuronic acid (MeGlcA).…”

Microbial Glucuronoyl Esterases: 10 Years after Discovery

“…Many synthetic substrates, such as alkyl and alkyl aryl alcohol esters of MeGlcA and GlcA or their glycosides used earlier (5,12,21,(33)(34)(35), are not commercially available. Natural sub- strates derived from plant cell wall material, such as suitable lignin-carbohydrate complexes, await their introduction.…”

“…The substrates enabled us to examine for the first time the presence of GE in commercial cellulolytic and hemicellulolytic preparations (38). However, as in the similar case of benzyl glucuronate, the lack of the 4-O-methyl group in GlcA decreases the affinity of the enzymes for the substrates (5,12,(33)(34)(35). It is obvious that methyl esters of analogous glycosides of MeGlcA could serve as ideal substrates.…”

Crystallization and preliminary X-ray diffraction analysis of the glucuronoyl esterase catalytic domain fromHypocrea jecorina

“…An enzyme that is capable of specifically hydrolyzing the alkyl and arylalkyl esters of MeGlcA (see Fig. 1) has been purified from the cellulolytic fungus Schizophyllum commune and named glucuronoyl esterase (GE; Š pá niková & Biely, 2006;Š pá niková et al, 2007). Based on the partial amino-acid sequence of this enzyme, genes coding for GEs in other fungi have recently been identified (Li et al, 2007).…”