2D2O
Structure of a complex of Thermoactinomyces vulgaris R-47 alpha-amylase 2 with maltohexaose demonstrates the important role of aromatic residues at the reducing end of the substrate binding cleft
Summary for 2D2O
| Entry DOI | 10.2210/pdb2d2o/pdb |
| Related | 1VFK 1VFM 1VFO 1VFU |
| Related PRD ID | PRD_900035 |
| Descriptor | Neopullulanase 2, alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose, CALCIUM ION, ... (4 entities in total) |
| Functional Keywords | beta/alpha barrel, hydrolase |
| Biological source | Thermoactinomyces vulgaris |
| Total number of polymer chains | 2 |
| Total formula weight | 137168.13 |
| Authors | Ohtaki, A.,Mizuno, M.,Yoshida, H.,Tonozuka, T.,Sakano, Y.,Kamitori, S. (deposition date: 2005-09-13, release date: 2006-08-29, Last modification date: 2024-05-29) |
| Primary citation | Ohtaki, A.,Mizuno, M.,Yoshida, H.,Tonozuka, T.,Sakano, Y.,Kamitori, S. Structure of a complex of Thermoactinomyces vulgaris R-47 alpha-amylase 2 with maltohexaose demonstrates the important role of aromatic residues at the reducing end of the substrate binding cleft Carbohydr.Res., 341:1041-1046, 2006 Cited by PubMed Abstract: Thermoactinomyces vulgaris R-47 alpha-amylase 2 (TVAII) can efficiently hydrolyze both starch and cyclomaltooligosaccharides (cyclodextrins). The crystal structure of an inactive mutant TVAII in a complex with maltohexaose was determined at a resolution of 2.1A. TVAII adopts a dimeric structure to form two catalytic sites, where substrates are found to bind. At the catalytic site, there are many hydrogen bonds between the enzyme and substrate at the non-reducing end from the hydrolyzing site, but few hydrogen bonds at the reducing end, where two aromatic residues, Trp356 and Tyr45, make effective interactions with a substrate. Trp356 drastically changes its side-chain conformation to achieve a strong stacking interaction with the substrate, and Tyr45 from another molecule forms a water-mediated hydrogen bond with the substrate. Kinetic analysis of the wild-type and mutant enzymes in which Trp356 and/or Tyr45 were replaced with Ala suggested that Trp356 and Tyr45 are essential to the catalytic reaction of the enzyme, and that the formation of a dimeric structure is indispensable for TVAII to hydrolyze both starch and cyclodextrins. PubMed: 16564038DOI: 10.1016/j.carres.2006.01.029 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2.1 Å) |
Structure validation
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