Predicting enzyme adsoprtion to lignin films from enzyme surface hydrophobicity

Published

May 29, 2014

Author(s)

Deanne W. Sammond, John M. Yarbrough, Elisabeth Mansfield, Yannick J. Bomble, Sarah Hobdey, Stephen R. Decker, Larry Taylor, Michael G. Resch, Michael E. Himmel, Todd B. Vinzant, Michael F. Crowley

Abstract

The loss of digestive activity of cellulase cocktails on biomass is a major challenge, commonly attributed to the binding of certain enzymes to lignin. While the binding mechanism remains unclear, hydrophobic interactions between enzymes and lignin are hypothesized to drive adsorption, with interactions governed by the presence of strongly hydrophobic protein regions. The hydrophobicity of the enzyme surface was quantified using mathematical estimation of the clustering of hydrophobic residues, identifying potential hydrophobic binding sites. We include proteins with no exposed hydrophobic patches larger than 100 Å2 as well as proteins with hydrophobic patches up to 450 Å2. The adsorption of enzymes to lignin surfaces, measured using the quartz crystal microbalance, was found to have a linear correlation to this hydrophobic cluster score for the proteins studied. These results suggest a minimum hydrophobic patch size needed for a protein to strongly, preferentially adsorb to lignin. Evaluating the role of electrostatic interactions in enzyme adsorption to lignin, the isoelectric point (pI) for each protein was compared to adsorption to lignin. There was no correlation between experimentally determined pI values and protein binding to lignin surfaces. Thus, while previous work shows altering buffer pH can alter enzyme adsorption to lignin, hydrophobicity appears to dictate adsorption at constant pH.

Citation

Journal of Biological Chemistry

Pub Type

Journals

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Citation

Sammond, D. , Yarbrough, J. , Mansfield, E. , Bomble, Y. , Hobdey, S. , Decker, S. , Taylor, L. , Resch, M. , Himmel, M. , Vinzant, T. and Crowley, M. (2014), Predicting enzyme adsoprtion to lignin films from enzyme surface hydrophobicity, Journal of Biological Chemistry, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=915864 (Accessed December 5, 2024)