Effect of multimodularity and spatial organization of glycoside hydrolases on catalysis

Abstract

The wide diversity among the carbohydrate-active enzymes (CAZymes) reflects the equally broad versatility in terms of composition and chemicals bonds found in the plant cell wall polymers on which they are active. This diversity is also expressed through the various strategies developed to circumvent the recalcitrance of these substrates to biological degradation. Glycoside hydrolases (GHs) are the most abundant of the CAZymes and are expressed as isolated catalytic modules or in association with carbohydrate-binding module (CBM), acting in synergism within complex arrays of enzymes. This multimodularity can be even more complex. The cellulosome presents a scaffold protein immobilized to the outer membrane of some microorganisms on which enzymes are grafted to prevent their dispersion and increase catalytic synergism. In polysaccharide utilization loci (PUL), GHs are also distributed across the membranes of some bacteria to co-ordinate the deconstruction of polysaccharides and the internalization of metabolizable carbohydrates. Although the study and characterization of these enzymatic activities need to take into account the entirety of this complex organization—in particular because of the dynamics involved in it—technical problems limit the present study to isolated enzymes. However, these enzymatic complexes also have a spatiotemporal organization, whose still neglected aspect must be considered. In the present review, the different levels of multimodularity that can occur in GHs will be reviewed, from its simplest forms to the most complex. In addition, attempts to characterize or study the effect on catalytic activity of the spatial organization within GHs will be addressed.

The Discovery of the Fucoidan-Active Endo-1→4-α-L-Fucanase of the GH168 Family, Which Produces Fucoidan Derivatives with Regular Sulfation and Anticoagulant Activity

“…Bacterial glycoside hydrolases often display a modular (syn. domain) organization of their polypeptide chains [ 46 ]. Such domains can perform a variety of auxiliary functions that may enhance the binding to the substrate, define the sub-cellular localization of the enzyme in bacteria, or maintain the correct orientation of the catalytic domain [ 46 , 47 , 48 ].…”

“…domain) organization of their polypeptide chains [ 46 ]. Such domains can perform a variety of auxiliary functions that may enhance the binding to the substrate, define the sub-cellular localization of the enzyme in bacteria, or maintain the correct orientation of the catalytic domain [ 46 , 47 , 48 ]. For example, some endo-fucanases of the GH107 family contained 3–4 additional domains in addition to the catalytic domain [ 21 , 30 ].…”

Insights into the Dynamic Succession of Microbial Community and Related Factors of Vanillin Content Change Based by High-Throughput Sequencing and Daqu Quality Drivers

“…The high relative abundance of GH may be due to the important role of GH in the hydrolysis and synthesis of biological sugars and glycoconjugates [47]. CBM plays an important role in the degradation of insoluble cellulose by cellulase [48]. Daqu is mostly made from grains, which contain various types of cellulose.…”