3W37
Sugar beet alpha-glucosidase with acarbose
Summary for 3W37
Entry DOI | 10.2210/pdb3w37/pdb |
Related | 3W38 3WEL 3WEM 3WEN 3WEO |
Related PRD ID | PRD_900007 |
Descriptor | Alpha-glucosidase, 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose, alpha-L-fucopyranose-(1-3)-[2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)]2-acetamido-2-deoxy-beta-D-glucopyranose, ... (9 entities in total) |
Functional Keywords | alpha-glucosidase, glycoside hydrolase family 31, (beta/alpha)8-barrel, acarbose, hydrolase, carbohydrate |
Biological source | Beta vulgaris (beet) |
Total number of polymer chains | 1 |
Total formula weight | 104926.47 |
Authors | Tagami, T.,Yamashita, K.,Okuyama, M.,Mori, H.,Yao, M.,Kimura, A. (deposition date: 2012-12-13, release date: 2013-05-29, Last modification date: 2024-10-30) |
Primary citation | Tagami, T.,Yamashita, K.,Okuyama, M.,Mori, H.,Yao, M.,Kimura, A. Molecular basis for the recognition of long-chain substrates by plant & alpha-glucosidase J.Biol.Chem., 288:19296-19303, 2013 Cited by PubMed Abstract: Sugar beet α-glucosidase (SBG), a member of glycoside hydrolase family 31, shows exceptional long-chain specificity, exhibiting higher kcat/Km values for longer malto-oligosaccharides. However, its amino acid sequence is similar to those of other short chain-specific α-glucosidases. To gain structural insights into the long-chain substrate recognition of SBG, a crystal structure complex with the pseudotetrasaccharide acarbose was determined at 1.7 Å resolution. The active site pocket of SBG is formed by a (β/α)8 barrel domain and a long loop (N-loop) bulging from the N-terminal domain similar to other related enzymes. Two residues (Phe-236 and Asn-237) in the N-loop are important for the long-chain specificity. Kinetic analysis of an Asn-237 mutant enzyme and a previous study of a Phe-236 mutant enzyme demonstrated that these residues create subsites +2 and +3. The structure also indicates that Phe-236 and Asn-237 guide the reducing end of long substrates to subdomain b2, which is an additional element inserted into the (β/α)8 barrel domain. Subdomain b2 of SBG includes Ser-497, which was identified as the residue at subsite +4 by site-directed mutagenesis. PubMed: 23687304DOI: 10.1074/jbc.M113.465211 PDB entries with the same primary citation |
Experimental method | X-RAY DIFFRACTION (1.7 Å) |
Structure validation
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