glycoside hydrolase family 38 (GH38) protein such as lysosomal alpha-mannosidase (LAM or Man2B1), which is a broad specificity exoglycosidase hydrolyzing all known alpha 1,2-, alpha 1,3-, and alpha 1,6-mannosidic linkages from numerous high mannose type oligosaccharides
N-terminal catalytic domain of lysosomal alpha-mannosidase and similar proteins; glycoside ...
2-276
7.08e-178
N-terminal catalytic domain of lysosomal alpha-mannosidase and similar proteins; glycoside hydrolase family 38 (GH38); The subfamily is represented by lysosomal alpha-mannosidase (LAM, Man2B1, EC 3.2.1.114), which is a broad specificity exoglycosidase hydrolyzing all known alpha 1,2-, alpha 1,3-, and alpha 1,6-mannosidic linkages from numerous high mannose type oligosaccharides. LAM is expressed in all tissues and in many species. In mammals, the absence of LAM can cause the autosomal recessive disease alpha-mannosidosis. LAM has an acidic pH optimum at 4.0-4.5. It is stimulated by zinc ion and is inhibited by cobalt ion and plant alkaloids, such as swainsonine (SW). LAM catalyzes hydrolysis by a double displacement mechanism in which a glycosyl-enzyme intermediate is formed and hydrolyzed via oxacarbenium ion-like transition states. A carboxylic acid in the active site acts as the catalytic nucleophile in the formation of the covalent intermediate while a second carboxylic acid acts as a general acid catalyst. The same residue is thought to assist in the hydrolysis (deglycosylation) step, this time acting as a general base.
:
Pssm-ID: 212121 [Multi-domain] Cd Length: 278 Bit Score: 516.38 E-value: 7.08e-178
N-terminal catalytic domain of lysosomal alpha-mannosidase and similar proteins; glycoside ...
2-276
7.08e-178
N-terminal catalytic domain of lysosomal alpha-mannosidase and similar proteins; glycoside hydrolase family 38 (GH38); The subfamily is represented by lysosomal alpha-mannosidase (LAM, Man2B1, EC 3.2.1.114), which is a broad specificity exoglycosidase hydrolyzing all known alpha 1,2-, alpha 1,3-, and alpha 1,6-mannosidic linkages from numerous high mannose type oligosaccharides. LAM is expressed in all tissues and in many species. In mammals, the absence of LAM can cause the autosomal recessive disease alpha-mannosidosis. LAM has an acidic pH optimum at 4.0-4.5. It is stimulated by zinc ion and is inhibited by cobalt ion and plant alkaloids, such as swainsonine (SW). LAM catalyzes hydrolysis by a double displacement mechanism in which a glycosyl-enzyme intermediate is formed and hydrolyzed via oxacarbenium ion-like transition states. A carboxylic acid in the active site acts as the catalytic nucleophile in the formation of the covalent intermediate while a second carboxylic acid acts as a general acid catalyst. The same residue is thought to assist in the hydrolysis (deglycosylation) step, this time acting as a general base.
Pssm-ID: 212121 [Multi-domain] Cd Length: 278 Bit Score: 516.38 E-value: 7.08e-178
Alpha mannosidase, middle domain; Members of this entry belong to the glycosyl hydrolase ...
323-398
4.75e-27
Alpha mannosidase, middle domain; Members of this entry belong to the glycosyl hydrolase family 38, This domain, which is found in the central region adopts a structure consisting of three alpha helices, in an immunoglobulin/albumin-binding domain-like fold. The domain is predominantly found in the enzyme alpha-mannosidase.
Pssm-ID: 214875 [Multi-domain] Cd Length: 79 Bit Score: 104.94 E-value: 4.75e-27
N-terminal catalytic domain of lysosomal alpha-mannosidase and similar proteins; glycoside ...
2-276
7.08e-178
N-terminal catalytic domain of lysosomal alpha-mannosidase and similar proteins; glycoside hydrolase family 38 (GH38); The subfamily is represented by lysosomal alpha-mannosidase (LAM, Man2B1, EC 3.2.1.114), which is a broad specificity exoglycosidase hydrolyzing all known alpha 1,2-, alpha 1,3-, and alpha 1,6-mannosidic linkages from numerous high mannose type oligosaccharides. LAM is expressed in all tissues and in many species. In mammals, the absence of LAM can cause the autosomal recessive disease alpha-mannosidosis. LAM has an acidic pH optimum at 4.0-4.5. It is stimulated by zinc ion and is inhibited by cobalt ion and plant alkaloids, such as swainsonine (SW). LAM catalyzes hydrolysis by a double displacement mechanism in which a glycosyl-enzyme intermediate is formed and hydrolyzed via oxacarbenium ion-like transition states. A carboxylic acid in the active site acts as the catalytic nucleophile in the formation of the covalent intermediate while a second carboxylic acid acts as a general acid catalyst. The same residue is thought to assist in the hydrolysis (deglycosylation) step, this time acting as a general base.
Pssm-ID: 212121 [Multi-domain] Cd Length: 278 Bit Score: 516.38 E-value: 7.08e-178
N-terminal catalytic domain of eukaryotic class II alpha-mannosidases; glycoside hydrolase ...
2-277
5.58e-109
N-terminal catalytic domain of eukaryotic class II alpha-mannosidases; glycoside hydrolase family 38 (GH38); The family corresponds to a group of eukaryotic class II alpha-mannosidases (AlphaMII), which contain Golgi alpha-mannosidases II (GMII), the major broad specificity lysosomal alpha-mannosidases (LAM, MAN2B1), the noval core-specific lysosomal alpha 1,6-mannosidases (Epman, MAN2B2), and similar proteins. GMII catalyzes the hydrolysis of the terminal both alpha-1,3-linked and alpha-1,6-linked mannoses from the high-mannose oligosaccharide GlcNAc(Man)5(GlcNAc)2 to yield GlcNAc(Man)3(GlcNAc)2 (GlcNAc, N-acetylglucosmine), which is the committed step of complex N-glycan synthesis. LAM is a broad specificity exoglycosidase hydrolyzing all known alpha 1,2-, alpha 1,3-, and alpha 1,6-mannosidic linkages from numerous high mannose type oligosaccharides. Different from LAM, Epman can efficiently cleave only the alpha 1,6-linked mannose residue from (Man)3GlcNAc, but not (Man)3(GlcNAc)2 or other larger high mannose oligosaccharides, in the core of N-linked glycans. Members in this family are retaining glycosyl hydrolases of family GH38 that employs a two-step mechanism involving the formation of a covalent glycosyl enzyme complex. Two carboxylic acids positioned within the active site act in concert: one as a catalytic nucleophile and the other as a general acid/base catalyst.
Pssm-ID: 212095 [Multi-domain] Cd Length: 258 Bit Score: 337.28 E-value: 5.58e-109
N-terminal catalytic domain of Golgi alpha-mannosidase II, Spodoptera frugiperda Sf9 ...
3-328
5.13e-73
N-terminal catalytic domain of Golgi alpha-mannosidase II, Spodoptera frugiperda Sf9 alpha-mannosidase III, and similar proteins; glycoside hydrolase family 38 (GH38); This subfamily is represented by Golgi alpha-mannosidase II (GMII, also known as mannosyl-oligosaccharide 1,3- 1,6-alpha mannosidase, EC 3.2.1.114, Man2A1), a monomeric, membrane-anchored class II alpha-mannosidase existing in the Golgi apparatus of eukaryotes. GMII plays a key role in the N-glycosylation pathway. It catalyzes the hydrolysis of the terminal both alpha-1,3-linked and alpha-1,6-linked mannoses from the high-mannose oligosaccharide GlcNAc(Man)5(GlcNAc)2 to yield GlcNAc(Man)3(GlcNAc)2(GlcNAc, N-acetylglucosmine), which is the committed step of complex N-glycan synthesis. GMII is activated by zinc or cobalt ions and is strongly inhibited by swainsonine. Inhibition of GMII provides a route to block cancer-induced changes in cell surface oligosaccharide structures. GMII has a pH optimum of 5.5-6.0, which is intermediate between those of acidic (lysosomal alpha-mannosidase) and neutral (ER/cytosolic alpha-mannosidase) enzymes. GMII is a retaining glycosyl hydrolase of family GH38 that employs a two-step mechanism involving the formation of a covalent glycosyl enzyme complex; two carboxylic acids positioned within the active site act in concert: one as a catalytic nucleophile and the other as a general acid/base catalyst. This subfamily also includes human alpha-mannosidase 2x (MX, also known as mannosyl-oligosaccharide 1,3- 1,6-alpha mannosidase, EC 3.2.1.114, Man2A2). MX is enzymatically and functionally very similar to GMII, and is thought to also function in the N-glycosylation pathway. Also found in this subfamily is class II alpha-mannosidase encoded by Spodoptera frugiperda Sf9 cell. This alpha-mannosidase is an integral membrane glycoprotein localized in the Golgi apparatus. It shows high sequence homology with mammalian Golgi alpha-mannosidase II(GMII). It can hydrolyze p-nitrophenyl alpha-D-mannopyranoside (pNP-alpha-Man), and it is inhibited by swainsonine. However, the Sf9 enzyme is stimulated by cobalt and can hydrolyze (Man)5(GlcNAc)2 to (Man)3(GlcNAc)2, but it cannot hydrolyze GlcNAc(Man)5(GlcNAc)2, which is distinct from that of GMII. Thus, this enzyme has been designated as Sf9 alpha-mannosidase III (SfManIII). It probably functions in an alternate N-glycan processing pathway in Sf9 cells.
Pssm-ID: 212120 [Multi-domain] Cd Length: 340 Bit Score: 244.48 E-value: 5.13e-73
N-terminal catalytic domain of class II alpha-mannosidases and similar proteins; glycoside ...
3-276
4.42e-63
N-terminal catalytic domain of class II alpha-mannosidases and similar proteins; glycoside hydrolase family 38 (GH38); Alpha-mannosidases (EC 3.2.1.24) are extensively found in eukaryotes and play important roles in the processing of newly formed N-glycans and in degradation of mature glycoproteins. A deficiency of this enzyme causes the lysosomal storage disease alpha-mannosidosis. Many bacterial and archaeal species also possess putative alpha-mannosidases, but their activity and specificity is largely unknown. Based on different functional characteristics and sequence homology, alpha-mannosidases have been organized into two classes (class I, belonging to glycoside hydrolase family 47, and class II, belonging to glycoside hydrolase family 38). Members of this family corresponds to class II alpha-mannosidases (alphaMII), which contain intermediate Golgi alpha-mannosidases II, acidic lysosomal alpha-mannosidases, animal sperm and epididymal alpha -mannosidases, neutral ER/cytosolic alpha-mannosidases, and some putative prokaryotic alpha-mannosidases. AlphaMII possess a-1,3, a-1,6, and a-1,2 hydrolytic activity, and catalyzes the degradation of N-linked oligosaccharides. The N-terminal catalytic domain of alphaMII adopts a structure consisting of parallel 7-stranded beta/alpha barrel. Members in this family are retaining glycosyl hydrolases of family GH38 that employs a two-step mechanism involving the formation of a covalent glycosyl enzyme complex. Two carboxylic acids positioned within the active site act in concert: one as a catalytic nucleophile and the other as a general acid/base catalyst.
Pssm-ID: 212098 [Multi-domain] Cd Length: 251 Bit Score: 213.80 E-value: 4.42e-63
N-terminal catalytic domain of Golgi alpha-mannosidase IIx, and similar proteins; glycoside ...
2-328
9.60e-58
N-terminal catalytic domain of Golgi alpha-mannosidase IIx, and similar proteins; glycoside hydrolase family 38 (GH38); This subfamily is represented by human alpha-mannosidase 2x (MX, also known as mannosyl-oligosaccharide 1,3- 1,6-alpha mannosidase, EC 3.2.1.114, Man2A2). MX is enzymatically and functionally very similar to GMII (found in another subfamily), and as an isoenzyme of GMII. It is thought to also function in the N-glycosylation pathway. MX specifically hydrolyzes the same oligosaccharide substrate as does MII. It specifically removes two mannosyl residues from GlcNAc(Man)5(GlcNAc)2 to yield GlcNAc(Man)3(GlcNAc)2(GlcNAc, N-acetylglucosmine).
Pssm-ID: 212132 [Multi-domain] Cd Length: 344 Bit Score: 202.14 E-value: 9.60e-58
N-terminal catalytic domain of Golgi alpha-mannosidase II and similar proteins; glycoside ...
2-328
2.46e-54
N-terminal catalytic domain of Golgi alpha-mannosidase II and similar proteins; glycoside hydrolase family 38 (GH38); This subfamily is represented by Golgi alpha-mannosidase II (GMII, also known as mannosyl-oligosaccharide 1,3- 1,6-alpha mannosidase, EC 3.2.1.114, Man2A1), a monomeric, membrane-anchored class II alpha-mannosidase existing in the Golgi apparatus of eukaryotes. GMII plays a key role in the N-glycosylation pathway. It catalyzes the hydrolysis of the terminal of both alpha-1,3-linked and alpha-1,6-linked mannoses from the high-mannose oligosaccharide GlcNAc(Man)5(GlcNAc)2 to yield GlcNAc(Man)3(GlcNAc)2(GlcNAc, N-acetylglucosmine), which is the committed step of complex N-glycan synthesis. GMII is activated by zinc or cobalt ions and is strongly inhibited by swainsonine. Inhibition of GMII provides a route to block cancer-induced changes in cell surface oligosaccharide structures. GMII has a pH optimum of 5.5-6.0, which is intermediate between those of acidic (lysosomal alpha-mannosidase) and neutral (ER/cytosolic alpha-mannosidase) enzymes. GMII is a retaining glycosyl hydrolase of family GH38 that employs a two-step mechanism involving the formation of a covalent glycosyl enzyme complex; two carboxylic acids positioned within the active site act in concert: one as a catalytic nucleophile and the other as a general acid/base catalyst.
Pssm-ID: 212131 [Multi-domain] Cd Length: 344 Bit Score: 192.49 E-value: 2.46e-54
N-terminal catalytic domain of mammalian core-specific lysosomal alpha 1,6-mannosidase and ...
2-318
3.37e-50
N-terminal catalytic domain of mammalian core-specific lysosomal alpha 1,6-mannosidase and similar proteins; glycoside hydrolase family 38 (GH38); The subfamily is represented by a novel human core-specific lysosomal alpha 1,6-mannosidase (Epman, Man2B2) and similar proteins. Although it was previously named as epididymal alpha-mannosidase, Epman has a broadly distributed transcript expression profile. Different from the major broad specificity lysosomal alpha-mannosidases (LAM, MAN2B1), Epman is not associated with genetic alpha-mannosidosis that is caused by the absence of LAM. Furthermore, Epman has unique substrate specificity. It can efficiently cleave only the alpha 1,6-linked mannose residue from (Man)3GlcNAc, but not (Man)3(GlcNAc)2 or other larger high mannose oligosaccharides, in the core of N-linked glycans. In contrast, the major LAM can cleave all of the alpha-linked mannose residues from high mannose oligosaccharides except the core alpha 1,6-linked mannose residue. Moreover, it is suggested that the catalytic activity of Epman is dependent on prior action by di-N-acetyl-chitobiase (chitobiase), which indicates there is a functional cooperation between these two enzymes for the full and efficient catabolism of mammalian lysosomal N-glycan core structures. Epman has an acidic pH optimum. It is strongly stimulated by cobalt or zinc ions and strongly inhibited by furanose analogues swainsonine (SW) and 1,4-dideoxy-1,4-imino-d-mannitol (DIM).
Pssm-ID: 212122 [Multi-domain] Cd Length: 326 Bit Score: 180.08 E-value: 3.37e-50
Alpha mannosidase middle domain; Members of this family adopt a structure consisting of three ...
322-416
7.64e-30
Alpha mannosidase middle domain; Members of this family adopt a structure consisting of three alpha helices, in an immunoglobulin/albumin-binding domain-like fold. They are predominantly found in the enzyme alpha-mannosidase.
Pssm-ID: 462728 [Multi-domain] Cd Length: 98 Bit Score: 113.90 E-value: 7.64e-30
Alpha mannosidase, middle domain; Members of this entry belong to the glycosyl hydrolase ...
323-398
4.75e-27
Alpha mannosidase, middle domain; Members of this entry belong to the glycosyl hydrolase family 38, This domain, which is found in the central region adopts a structure consisting of three alpha helices, in an immunoglobulin/albumin-binding domain-like fold. The domain is predominantly found in the enzyme alpha-mannosidase.
Pssm-ID: 214875 [Multi-domain] Cd Length: 79 Bit Score: 104.94 E-value: 4.75e-27
N-terminal catalytic domain of endoplasmic reticulum(ER)/cytosolic class II alpha-mannosidases; ...
4-149
1.15e-10
N-terminal catalytic domain of endoplasmic reticulum(ER)/cytosolic class II alpha-mannosidases; glycoside hydrolase family 38 (GH38); The subfamily is represented by Saccharomyces cerevisiae vacuolar alpha-mannosidase Ams1, rat ER/cytosolic alpha-mannosidase Man2C1, and similar proteins. Members in this family share high sequence similarity. None of them have any classical signal sequence or membrane spanning domains, which are typical of sorting or targeting signals. Ams1 functions as a second resident vacuolar hydrolase in S. cerevisiae. It aids in recycling macromolecular components of the cell through hydrolysis of terminal, non-reducing alpha-d-mannose residues. Ams1 utilizes both the cytoplasm to vacuole targeting (Cvt, nutrient-rich conditions) and autophagic (starvation conditions) pathways for biosynthetic delivery to the vacuole. Man2C1is involved in oligosaccharide catabolism in both the ER and cytosol. It can catalyze the cobalt-dependent cleavage of alpha 1,2-, alpha 1,3-, and alpha 1,6-linked mannose residues. Members in this family are retaining glycosyl hydrolases of family GH38 that employs a two-step mechanism involving the formation of a covalent glycosyl-enzyme complex. Two carboxylic acids positioned within the active site act in concert: one as a catalytic nucleophile and the other as a general acid/base catalyst.
Pssm-ID: 212101 [Multi-domain] Cd Length: 252 Bit Score: 62.91 E-value: 1.15e-10
N-terminal catalytic domain of Escherichia coli alpha-mannosidase MngB and its bacterial ...
3-280
2.82e-10
N-terminal catalytic domain of Escherichia coli alpha-mannosidase MngB and its bacterial homologs; glycoside hydrolase family 38 (GH38); The bacterial subfamily is represented by Escherichia coli alpha-mannosidase MngB, which is encoded by the mngB gene (previously called ybgG). MngB exhibits alpha-mannosidase activity that converts 2-O-(6-phospho-alpha-mannosyl)-D-glycerate to mannose-6-phosphate and glycerate in the pathway which enables use of mannosyl-D-glycerate as a sole carbon source. A divalent metal ion is required for its activity.
Pssm-ID: 212126 [Multi-domain] Cd Length: 270 Bit Score: 62.16 E-value: 2.82e-10
N-terminal catalytic domain of yeast vacuolar alpha-mannosidases and similar proteins; ...
3-146
2.24e-06
N-terminal catalytic domain of yeast vacuolar alpha-mannosidases and similar proteins; glycoside hydrolase family 38 (GH38); The family is represented by Saccharomyces cerevisiae alpha-mannosidase (Ams1) and its eukaryotic homologs. Ams1 functions as a second resident vacuolar hydrolase in S. cerevisiae. It aids in recycling macromolecular components of the cell through hydrolysis of terminal, non-reducing alpha-d-mannose residues. Ams1 forms an oligomer in the cytoplasm and retains its oligomeric form during the import process. It utilizes both the Cvt (nutrient-rich conditions) and autophagic (starvation conditions) pathways for biosynthetic delivery to the vacuole. Mutants in either pathway are defective in Ams1 import. Members in this family show high sequence similarity with rat ER/cytosolic alpha-mannosidase Man2C1.
Pssm-ID: 212123 [Multi-domain] Cd Length: 258 Bit Score: 50.13 E-value: 2.24e-06
Catalytic domain of glycoside hydrolase (GH) families 38 and 57, lactam utilization protein ...
6-138
5.06e-06
Catalytic domain of glycoside hydrolase (GH) families 38 and 57, lactam utilization protein LamB/YcsF family proteins, YdjC-family proteins, and similar proteins; The superfamily possesses strong sequence similarities across a wide range of all three kingdoms of life. It mainly includes four families, glycoside hydrolases family 38 (GH38), heat stable retaining glycoside hydrolases family 57 (GH57), lactam utilization protein LamB/YcsF family, and YdjC-family. The GH38 family corresponds to class II alpha-mannosidases (alphaMII, EC 3.2.1.24), which contain intermediate Golgi alpha-mannosidases II, acidic lysosomal alpha-mannosidases, animal sperm and epididymal alpha -mannosidases, neutral ER/cytosolic alpha-mannosidases, and some putative prokaryotic alpha-mannosidases. AlphaMII possess a-1,3, a-1,6, and a-1,2 hydrolytic activity, and catalyzes the degradation of N-linked oligosaccharides by employing a two-step mechanism involving the formation of a covalent glycosyl enzyme complex. GH57 is a purely prokaryotic family with the majority of thermostable enzymes from extremophiles (many of them are archaeal hyperthermophiles), which exhibit the enzyme specificities of alpha-amylase (EC 3.2.1.1), 4-alpha-glucanotransferase (EC 2.4.1.25), amylopullulanase (EC 3.2.1.1/41), and alpha-galactosidase (EC 3.2.1.22). This family also includes many hypothetical proteins with uncharacterized activity and specificity. GH57 cleaves alpha-glycosidic bond by employing a retaining mechanism, which involves a glycosyl-enzyme intermediate, allowing transglycosylation. Although the exact molecular function of LamB/YcsF family and YdjC-family remains unclear, they show high sequence and structure homology to the members of GH38 and GH57. Their catalytic domains adopt a similar parallel 7-stranded beta/alpha barrel, which is remotely related to catalytic NodB homology domain of the carbohydrate esterase 4 superfamily.
Pssm-ID: 212097 [Multi-domain] Cd Length: 203 Bit Score: 48.41 E-value: 5.06e-06
N-terminal catalytic domain of SPGH38, a putative alpha-mannosidase of Streptococcus pyogenes, ...
4-276
1.80e-04
N-terminal catalytic domain of SPGH38, a putative alpha-mannosidase of Streptococcus pyogenes, and its prokaryotic homologs; glycoside hydrolase family 38 (GH38); The subfamily is represented by SpGH38 of Streptococcus pyogenes, which has been assigned as a putative alpha-mannosidase, and is encoded by ORF spy1604. SpGH38 appears to exist as an elongated dimer and display alpha-1,3 mannosidase activity. It is active on disaccharides and some aryl glycosides. SpGH38 can also effectively deglycosylate human N-glycans in vitro. A divalent metal ion, such as a zinc ion, is required for its activity. SpGH38 is inhibited by swainsonine. The absence of any secretion signal peptide suggests that SpGH38 may be intracellular.
Pssm-ID: 212125 [Multi-domain] Cd Length: 271 Bit Score: 44.56 E-value: 1.80e-04
N-terminal catalytic domain of mainly uncharacterized eukaryotic proteins similar to ...
4-149
2.34e-04
N-terminal catalytic domain of mainly uncharacterized eukaryotic proteins similar to alpha-mannosidases; glycoside hydrolase family 38 (GH38); The subfamily of mainly uncharacterized eukaryotic proteins shows sequence homology with class II alpha-mannosidases (AlphaAMIIs). AlphaAMIIs possess a-1,3, a-1,6, and a-1,2 hydrolytic activity, and catalyze the degradation of N-linked oligosaccharides. The N-terminal catalytic domain of alphaMII adopts a structure consisting of parallel 7-stranded beta/alpha barrel. This subfamily belongs to the GH38 family of retaining glycosyl hydrolases, which employ a two-step mechanism involving the formation of a covalent glycosyl enzyme complex; two carboxylic acids positioned within the active site act in concert: one as a catalytic nucleophile and the other as a general acid/base catalyst.
Pssm-ID: 212103 [Multi-domain] Cd Length: 254 Bit Score: 43.84 E-value: 2.34e-04
N-terminal catalytic domain of putative prokaryotic class II alpha-mannosidases; glycoside ...
4-199
4.92e-04
N-terminal catalytic domain of putative prokaryotic class II alpha-mannosidases; glycoside hydrolase family 38 (GH38); This mainly bacterial subfamily corresponds to a group of putative class II alpha-mannosidases, including various proteins assigned as alpha-mannosidases, Streptococcus pyogenes (SpGH38) encoded by ORF spy1604. Escherichia coli MngB encoded by the mngB/ybgG gene, and Thermotoga maritime TMM, and similar proteins. SpGH38 targets alpha-1,3 mannosidic linkages. SpGH38 appears to exist as an elongated dimer and display alpha-1,3 mannosidase activity. It is active on disaccharides and some aryl glycosides. SpGH38 can also effectively deglycosylate human N-glycans in vitro. MngB exhibits alpha-mannosidase activity that catalyzes the conversion of 2-O-(6-phospho-alpha-mannosyl)-D-glycerate to mannose-6-phosphate and glycerate in the pathway which enables use of mannosyl-D-glycerate as a sole carbon source. TMM is a homodimeric enzyme that hydrolyzes p-nitrophenyl-alpha-D-mannopyranoside, alpha -1,2-mannobiose, alpha -1,3-mannobiose, alpha -1,4-mannobiose, and alpha -1,6-mannobiose. The GH38 family contains retaining glycosyl hydrolases that employ a two-step mechanism involving the formation of a covalent glycosyl enzyme complex. Two carboxylic acids positioned within the active site act in concert: one as a catalytic nucleophile and the other as a general acid/base catalyst. Divalent metal ions, such as zinc or cobalt ions, are suggested to be required for the catalytic activities of typical class II alpha-mannosidases. However, TMM requires the cobalt or cadmium for its activity. The cadmium ion dependency is unique to TMM. Moreover, TMM is inhibited by swainsonine but not 1-deoxymannojirimycin, which is in agreement with the features of cytosolic alpha-mannosidase.
Pssm-ID: 212102 [Multi-domain] Cd Length: 273 Bit Score: 43.22 E-value: 4.92e-04
N-terminal catalytic domain of mammalian cytosolic alpha-mannosidase Man2C1 and similar ...
4-149
3.13e-03
N-terminal catalytic domain of mammalian cytosolic alpha-mannosidase Man2C1 and similar proteins; glycoside hydrolase family 38 (GH38); The subfamily corresponds to cytosolic alpha-mannosidase Man2C1 (also known as ER-mannosidase II or neutral/cytosolic mannosidase), mainly found in various vertebrates, and similar proteins. Man2C1 plays an essential role in the catabolism of cytosolic free oligomannosides derived from dolichol intermediates and the degradation of newly synthesized glycoproteins in ER or cytosol. It can catalyze the cleavage of alpha 1,2-, alpha 1,3-, and alpha 1,6-linked mannose residues. Man2C1 is a cobalt-dependent enzyme belonging to alpha-mannosidase class II. It has a neutral pH optimum and is strongly inhitibed by furanose analogs swainsonine (SW) and 1,4-dideoxy-1,4-imino-D-mannitol (DIM), moderately by deoxymannojirimycin (DMM), but not by kifunensine (KIF). DMM and KIF, both pyranose analogs, are normally known to inhibit class I alpha-mannosidase.
Pssm-ID: 212124 [Multi-domain] Cd Length: 252 Bit Score: 40.45 E-value: 3.13e-03
Database: CDSEARCH/cdd Low complexity filter: no Composition Based Adjustment: yes E-value threshold: 0.01
References:
Wang J et al. (2023), "The conserved domain database in 2023", Nucleic Acids Res.51(D)384-8.
Lu S et al. (2020), "The conserved domain database in 2020", Nucleic Acids Res.48(D)265-8.
Marchler-Bauer A et al. (2017), "CDD/SPARCLE: functional classification of proteins via subfamily domain architectures.", Nucleic Acids Res.45(D)200-3.
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