Table 2.
Glycoside hydrolase (GH) and carbohydrate‐binding module (CBM) profiles of intestinal microbiota in Chinese concave‐eared frogs in relation to chitin degradation. Data are presented as the sum number of genes encoding the corresponding enzyme
| RTF | RTM | Total | Known chitin degradation activities | |
|---|---|---|---|---|
| Chitinases | ||||
| GH18 | 109 | 57 | 163 | Chitinase; lysozyme; endo‐β‐N‐acetylglucosaminidase; peptidoglycan hydrolase with endo‐β‐N‐acetylglucosaminidase; others |
| GH19 | 8 | 16 | 24 | Chitinase; lysozyme |
| GH23 | 137 | 116 | 253 | Lysozyme type G; peptidoglycan lyase; chitinase |
| Chitosanase | ||||
| GH7 | 0 | 1 | 1 | Endo‐β‐1,4‐glucanase; reducing end‐acting cellobiohydrolase; chitosanase; endo‐β‐1,3‐1,4‐glucanase |
| GH8 | 12 | 4 | 16 | Chitosanase; cellulase; licheninase; endo‐1,4‐β‐xylanase; reducing‐end xylose‐releasing exo‐oligoxylanase |
| GH46 | 8 | 1 | 9 | Chitosanase |
| GH75 | 3 | 1 | 4 | Chitosanase |
| GH80 | 1 | 0 | 1 | Chitosanase |
| Lysozyme | ||||
| GH18 | 106 | 57 | 163 | Chitinase; lysozyme; endo‐β‐N‐acetylglucosaminidase; peptidoglycan hydrolase with endo‐β‐N‐acetylglucosaminidase; others |
| GH19 | 8 | 16 | 24 | Chitinase; lysozyme |
| GH22 | 0 | 2 | 2 | Lysozyme type C; lysozyme type i; α‐lactalbumin |
| GH24 | 31 | 39 | 70 | Lysozyme |
| Cellulases | ||||
| GH5 | 57 | 27 | 84 | Endo‐β‐1,4‐glucanase/cellulase; endo‐β‐1,4‐xylanase; β‐glucosidase; β‐mannosidase; others |
| GH8 | 12 | 4 | 16 | Chitosanase; cellulase; licheninase; endo‐1,4‐β‐xylanase; reducing‐end‐xylose releasing exo‐oligoxylanase |
| N‐acetylglucosaminidase | ||||
| GH18 | 106 | 57 | 163 | Chitinase; lysozyme; endo‐β‐N‐acetylglucosaminidase; peptidoglycan hydrolase with endo‐β‐N‐acetylglucosaminidase; others |
| GH20 | 209 | 91 | 300 | β‐hexosaminidase; lacto‐N‐biosidase; β‐1,6‐N‐acetylglucosaminidase; β‐6‐SO3‐N‐acetylglucosaminidase |
| GH73 | 98 | 58 | 156 | Lysozyme; mannosyl‐glycoprotein endo‐β‐N‐acetylglucosaminidase; peptidoglycan hydrolase with endo‐β‐N‐acetylglucosaminidase specificity |
| GH84 | 43 | 23 | 66 | N‐acetyl β‐glucosaminidase; hyaluronidase; [protein]‐3‐O‐(GlcNAc)‐l‐Ser/Thr β‐N‐acetylglucosaminidase |
| GH85 | 10 | 4 | 14 | Endo‐β‐N‐acetylglucosaminidase |
| GH89 | 38 | 22 | 60 | α‐N‐acetylglucosaminidase |
| GH111 | 1 | 0 | 1 | Keratan sulfate hydrolase (endo‐β‐N‐acetylglucosaminidase) |
| GH116 | 16 | 13 | 29 | β‐glucosidase; β‐xylosidase; acid β‐glucosidase/β‐glucosylceramidase; β‐N‐acetylglucosaminidase |
| Chitin‐binding function | ||||
| CBM2 | 2 | 10 | 12 | Several of these modules have been shown to also bind chitin or xylan; others |
| CBM3 | 3 | 0 | 3 | In one instance binding to chitin has been reported; others |
| CBM5 | 983 | 19 | 992 | Chitin‐binding described in several cases; others |
| CBM12 | 23 | 17 | 40 | The majority of these modules is found among chitinases where the function is chitin‐binding; others |
| CBM14 | 3 | 2 | 5 | The chitin‐binding function has been demonstrated in several cases; others |
| CBM18 | 0 | 1 | 1 | The chitin‐binding function has been demonstrated in many cases. These modules are found attached to a number of chitinase catalytic domains, but also in non‐catalytic proteins either in isolation or as multiple repeats; others |
| CBM19 | 0 | 2 | 2 | Modules of 60–70 residues with chitin‐binding function |
| CBM73 | 5 | 1 | 6 | Modules of approx 65 residues found on various enzymes active of chitin. Chitin‐binding function demonstrated for the Cellvibrio japonicus CjLPMO10A protein |