In Silico Comparison of the Hemicelluloses Xyloglucan and Glucuronoarabinoxylan in Protecting Cellulose from DegradationReport as inadecuate




In Silico Comparison of the Hemicelluloses Xyloglucan and Glucuronoarabinoxylan in Protecting Cellulose from Degradation - Download this document for free, or read online. Document in PDF available to download.

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AgResearch Limited, Ruakura Research Centre, Private Bag 3123, Hamilton 3240, New Zealand

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AgResearch Limited, Grasslands Research Centre, Private Bag 11008, Palmerston North 4442, New Zealand

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School of Biological Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand





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Academic Editor: Rainer Breitling

Abstract We used a previously developed simulation model of a plant cell wall and its enzymatic degradation to compare the abilities of two hemicelluloses, glucuronoarabinoxylan GAX and xyloglucan XG, to protect cellulose microfibrils CMFs from attack by cellulose-degrading enzymes. Additionally, we investigated the effect of XG abundance on the degradation rate of CMFs in the presence of the same enzymes. Simulations were run using hypothetical cell-wall compositions in which the numbers and arrangement of CMFs and 1,3;1,4-β-glucan were kept constant, but the proportions of GAX and XG were altered. Scenarios considered walls with low and equal proportions of either GAX or XG, and also low, medium and high proportions of XG in the absence of GAX. The rate of CMF degradation was much lower in walls with GAX than walls with XG, except for early in the simulation when the reverse held, suggesting that XGs were protecting CMFs by competitive inhibition. Increasing XG content reduced both the degradation rate of CMFs and the percent of XG degraded, indicating that activity of enzymes decreased with XG density despite XG being degradable. Glucose oligosaccharide breakdown products were analysed on the basis of the originating polysaccharide and their degree of polymerisation DP. The presence of GAX as opposed to equal amounts of XG had some significant effects on the amount and profile of breakdown products from XG and CMFs. View Full-Text

Keywords: plant cell wall; lignocellulose; enzymatic degradation; enzymes; accessibility; competitive inhibition; rumen; second-generation biofuels, agent-based modelling; simulation model plant cell wall; lignocellulose; enzymatic degradation; enzymes; accessibility; competitive inhibition; rumen; second-generation biofuels, agent-based modelling; simulation model





Author: Indrakumar Vetharaniam 1,* , Martin Upsdell 1, William J. Kelly 2, Graeme T. Attwood 2, Christina D. Moon 2 and Philip J. Harris 3

Source: http://mdpi.com/



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