3LPO
Crystal structure of the N-terminal domain of sucrase-isomaltase
Summary for 3LPO
| Entry DOI | 10.2210/pdb3lpo/pdb |
| Related | 3LPP |
| Descriptor | Sucrase-isomaltase, 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose, alpha-D-mannopyranose-(1-3)-[alpha-D-mannopyranose-(1-6)]beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose, ... (4 entities in total) |
| Functional Keywords | glycoside hydrolase family 31, isomaltase, alpha-glucosidase, cell membrane, disease mutation, disulfide bond, glycoprotein, glycosidase, hydrolase, membrane, multifunctional enzyme, polymorphism, signal-anchor, sulfation, transmembrane |
| Biological source | Homo sapiens (human) |
| Cellular location | Apical cell membrane; Single-pass type II membrane protein: P14410 |
| Total number of polymer chains | 4 |
| Total formula weight | 415245.08 |
| Authors | Sim, L.,Rose, D.R. (deposition date: 2010-02-05, release date: 2010-03-31, Last modification date: 2024-10-09) |
| Primary citation | Sim, L.,Willemsma, C.,Mohan, S.,Naim, H.Y.,Pinto, B.M.,Rose, D.R. Structural basis for substrate selectivity in human maltase-glucoamylase and sucrase-isomaltase N-terminal domains. J.Biol.Chem., 285:17763-17770, 2010 Cited by PubMed Abstract: Human maltase-glucoamylase (MGAM) and sucrase-isomaltase (SI) are small intestinal enzymes that work concurrently to hydrolyze the mixture of linear alpha-1,4- and branched alpha-1,6-oligosaccharide substrates that typically make up terminal starch digestion products. MGAM and SI are each composed of duplicated catalytic domains, N- and C-terminal, which display overlapping substrate specificities. The N-terminal catalytic domain of human MGAM (ntMGAM) has a preference for short linear alpha-1,4-oligosaccharides, whereas N-terminal SI (ntSI) has a broader specificity for both alpha-1,4- and alpha-1,6-oligosaccharides. Here we present the crystal structure of the human ntSI, in apo form to 3.2 A and in complex with the inhibitor kotalanol to 2.15 A resolution. Structural comparison with the previously solved structure of ntMGAM reveals key active site differences in ntSI, including a narrow hydrophobic +1 subsite, which may account for its additional substrate specificity for alpha-1,6 substrates. PubMed: 20356844DOI: 10.1074/jbc.M109.078980 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (3.2 Å) |
Structure validation
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