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.

mannosylglycerate hydrolase.

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.

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.

Alpha-mannosidase [Carbohydrate transport and metabolism].

Thecrystal structure of an alpha-mannosidase from Enterococcus faecalis V583 [Enterococcus faecalis V583],5KBP_B The crystal structure of an alpha-mannosidase from Enterococcus faecalis V583 [Enterococcus faecalis V583]

Structureof the Streptococcus pyogenes family GH38 alpha-mannosidase [Streptococcus pyogenes M1 GAS],2WYH_B Structure of the Streptococcus pyogenes family GH38 alpha-mannosidase [Streptococcus pyogenes M1 GAS],2WYI_A Structure of the Streptococcus pyogenes family GH38 alpha-mannosidase complexed with swainsonine [Streptococcus pyogenes M1 GAS],2WYI_B Structure of the Streptococcus pyogenes family GH38 alpha-mannosidase complexed with swainsonine [Streptococcus pyogenes M1 GAS]

TheCrystal Structure of a Protein in the Glycosyl Hydrolase Family 38 from Enterococcus faecalis to 2.55A [Enterococcus faecalis V583]

Mannosylglycerate hydrolase OS=Escherichia coli (strain K12) OX=83333 GN=mngB PE=1 SV=2

Putative mannosylglycerate hydrolase OS=Alkalihalobacillus halodurans (strain ATCC BAA-125 / DSM 18197 / FERM 7344 / JCM 9153 / C-125) OX=272558 GN=mngB PE=3 SV=2