Carbohydrate-binding modules targeting branched polysaccharides: overcoming side-chain recalcitrance in a non-catalytic approach

Abstract

Extensive decoration of backbones is a major factor resulting in resistance of enzymatic conversion in hemicellulose and other branched polysaccharides. Employing debranching enzymes is the main strategy to overcome this kind of recalcitrance at present. A carbohydrate-binding module (CBM) is a contiguous amino acid sequence that can promote the binding of enzymes to various carbohydrates, thereby facilitating enzymatic hydrolysis. According to previous studies, CBMs can be classified into four types based on their preference in ligand type, where Type III and IV CBMs prefer to branched polysaccharides than the linear and thus are able to specifically enhance the hydrolysis of substrates containing side chains. With a role in dominating the hydrolysis of branched substrates, Type III and IV CBMs could represent a non-catalytic approach in overcoming side-chain recalcitrance.

Proteoglycan Extracted from Ganoderma lucidum Ameliorated Diabetes-Induced Muscle Atrophy via the AMPK/SIRT1 Pathway In Vivo and In Vitro

“…Moreover, it has been reported that the CBM motif tends to bind carbohydrates, for example, polysaccharides. 58 Therefore, the function of FYGL in activating AMPK may be attributed to its abundant hydroxyl groups in the polysaccharide moieties. 16 The PI3K-AKT−mTOR pathway also plays an important role in regulating skeletal muscle growth, and activation of PI3K/AKT signaling can stimulate protein synthesis and inhibit protein degradation.…”

“…Research has shown that many reported AMPK activators such as astaxanthin, quercetin, and canagliflozin contain hydroxyl groups, indicating that hydroxyl groups are beneficial to their binding to the CBM-KD interface. Moreover, it has been reported that the CBM motif tends to bind carbohydrates, for example, polysaccharides . Therefore, the function of FYGL in activating AMPK may be attributed to its abundant hydroxyl groups in the polysaccharide moieties …”

Heterologous Expression of a Thermostable α-Galactosidase from Parageobacillus thermoglucosidasius Isolated from the Lignocellulolytic Microbial Consortium TMC7

“…Previous metagenomic analysis has shown that Geobacillus encoded enzymes are associated with the debranching of hemicellulose. Since hemicellulose contains heteropolysaccharides with different side chains, the catabolism of hemicellulose requires various debranching enzymes [ 43 ]. Significant synergistic effects between α-galactosidases and mannosidase have been documented in the degradation of carob gum [ 44 ].…”

The carbohydrate-binding module mediates mCherry protein anchoring on the cell wall in rice

“…This type of CBM has a slit or cavity on the surface, which can bind to a wide variety of glycans, such as xylans, mannans, galactans and starch (Armenta et al 2017). Type C CBM is a small molecule sugar-bound type (Boraston et al 2004) including family 9, 13, 14, 18, etc, and their binding substrates are limited to monosaccharide, oligosaccharide, or polysaccharide terminal sugar groups (Liu et al 2021). Therefore, the target and speci city for substrate recognition of carbohydrates make CBM a good domain structure for anchoring on the cell wall of plants.…”