Molecular insights of a xyloglucan endo-transglycosylase/hydrolase of radiata pine (PrXTH1) expressed in response to inclination: Kinetics and computational study.
Xyloglucan endotransglycosylase/hydrolases (XTH) may have endotransglycosylase (XET) and/or hydrolase (XEH) activities. Previous studies confirmed XET activity for PrXTH1 protein from radiata pine. XTHs could interact with many hemicellulose substrates, but the favorite substrate of PrXTH1 is still unknown. The prediction of union type and energy stability of the complexes formed between PrXTH1 and different substrates (XXXGXXXG, XXFGXXFG, XLFGXLFG and cellulose) were determined using bioinformatics tools. Molecular Docking, Molecular Dynamics, MM-GBSA and Electrostatic Potential Calculations were employed to predict the binding modes, free energies of interaction and the distribution of electrostatic charge. The results suggest that the enzyme formed more stable complexes with hemicellulose substrates than cellulose, and the best ligand was the xyloglucan XLFGXLFG (free energy of -58.83 ± 0.8 kcal mol-1). During molecular dynamics trajectories, hemicellulose fibers showed greater stability than cellulose. Aditionally, the kinetic properties of PrXTH1 enzyme were determined. The recombinant protein was active and showed an optimal pH 5.0 and optimal temperature of 37 °C. A Km value of 20.9 mM was determined for xyloglucan oligomer. PrXTH1 is able to interact with different xyloglycans structures but no activity was observed for cellulose as substrate, remodeling cell wall structure in response to inclination.
['Morales-Quintana|Luis|L|', 'Carrasco-Orellana|Cristian|C|', 'Beltrán|Dina|D|', 'Moya-León|María Alejandra|MA|', 'Herrera|Raúl|R|']
D002473:Cell Wall D003001:Cloning, Molecular D018506:Gene Expression Regulation, Plant D016695:Glycosyltransferases D007700:Kinetics D062105:Molecular Docking Simulation D010843:Pichia D010940:Plant Proteins D011994:Recombinant Proteins D013379:Substrate Specificity
Xyloglucan endotransglycosylase/hydrolases Xyloglycans Enzymatic parameters Plant cell wall