Structural analysis of rice Os4BGlu18 monolignol β-glucosidase

Abstract

Monolignol glucosides are storage forms of monolignols, which are polymerized to lignin to strengthen plant cell walls. The conversion of monolignol glucosides to monolignols is catalyzed by monolignol β-glucosidases. Rice Os4BGlu18 β-glucosidase catalyzes hydrolysis of the monolignol glucosides, coniferin, syringin, and p-coumaryl alcohol glucoside more efficiently than other natural substrates. To understand more clearly the basis for substrate specificity of a monolignol β-glucosidase, the structure of Os4BGlu18 was determined by X-ray crystallography. Crystals of Os4BGlu18 and its complex with δ-gluconolactone diffracted to 1.7 and 2.1 Å resolution, respectively. Two protein molecules were found in the asymmetric unit of the P212121 space group of their isomorphous crystals. The Os4BGlu18 structure exhibited the typical (β/α)8 TIM barrel of glycoside hydrolase family 1 (GH1), but the four variable loops and two disulfide bonds appeared significantly different from other known structures of GH1 β-glucosidases. Molecular docking studies of the Os4BGlu18 structure with monolignol substrate ligands placed the glycone in a similar position to the δ-gluconolactone in the complex structure and revealed the interactions between protein and ligands. Molecular docking, multiple sequence alignment, and homology modeling identified amino acid residues at the aglycone-binding site involved in substrate specificity for monolignol β-glucosides. Thus, the structural basis of substrate recognition and hydrolysis by monolignol β-glucosidases was elucidated.

In silico analysis and transcript levels of non-specific lipid transfer proteins (SiLTPI.5 and SiLTPII.1) under abiotic stresses in sesame (Sesamum indicum)

“…Molecular docking was executed using Autodock 4.2 (ADT version 1.5.6; Baiya et al, 2021) to consider the interactions of SiLTPI.5 and SiLTPII.1 with 22 ligands that had been reported as potential ligands for nsLTP. The ligands were retrieved from the Protein Data Bank (https://www.rcsb.org).…”

Avaliação do potencial biotecnológico de uma nova β-glicosidase do fungo Aspergillus fumigatus

“…A partir do gel, pode-se observar que a banda proteica correspondente a AfBgl1.3 recombinante apresentou uma massa molecular estimada de 54 kDa, o que corresponde ao tamanho previsto para a proteína. que correspondem ao resíduo ácido/básico catalítico e ao resíduo nucleofílico catalítico, respectivamente, destacados na Figura 14 (JENG et al, 2011;FLORINDO et al, 2018;LIEW et al, 2018;BAIYA et al, 2021). Além disso, foi possível identificar motivos conservados para β-glicosidases da família GH1, como o motivo N-terminal, que compreende 15 aminoácidos, cuja sequência é dada por:…”