Structural Dynamics, Mechanism, and Interaction of Lytic Polysaccharide Monooxygenases and Cellobiose Dehydrogenase

Abstract

For bioethanol production from lignocellulosic biomass, an enzyme cocktail is used, where these enzymes act synergistically to breakdown the polymeric structure of cellulose to simple sugars. Among the cocktail, is Lytic Polysaccharide Monooxygenase (LPMO) that has the ability to act on crystalline form of cellulose. Study on LPMOs is interesting due to this property and for its optimal activity, a reducing agent is required, which is usually Cellobiose dehydrogenase (CDH). The activation of LPMO occurs by means of electron transfer within CDH and then from CDH to LPMO. The structural and dynamical duet of LPMO and CDH and their interactions are unexplored till date. In this study, I have identified the conformational changes using computational approaches. My hypothesis is that there are key residues that are responsible for LPMO binding with CDH, and for transfer of the electron to LPMO. Also, there is a highly likely event of an allosteric change occurring in either CDH or in LPMO during binding, where the conformational change between the flavin and heme domains of CDH may possibly influence the electron transfer process. I discuss the conformational sampling using Elastic Network Models