6AG0
The X-ray Crystallographic Structure of Maltooligosaccharide-forming Amylase from Bacillus stearothermophilus STB04
Summary for 6AG0
| Entry DOI | 10.2210/pdb6ag0/pdb |
| Related PRD ID | PRD_900007 |
| Descriptor | Alpha-amylase, 4,6-dideoxy-4-{[(1S,4R,5S,6S)-4,5,6-trihydroxy-3-(hydroxymethyl)cyclohex-2-en-1-yl]amino}-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose, CALCIUM ION, ... (4 entities in total) |
| Functional Keywords | maltotetraose-forming amylase, bacillus stearothermophilus stb04, sugar binding protein |
| Biological source | Geobacillus stearothermophilus (Bacillus stearothermophilus) |
| Total number of polymer chains | 2 |
| Total formula weight | 130579.75 |
| Authors | |
| Primary citation | Xie, X.,Li, Y.,Ban, X.,Zhang, Z.,Gu, Z.,Li, C.,Hong, Y.,Cheng, L.,Jin, T.,Li, Z. Crystal structure of a maltooligosaccharide-forming amylase from Bacillus stearothermophilus STB04. Int.J.Biol.Macromol., 138:394-402, 2019 Cited by PubMed Abstract: To better understand structure-function relationships, an X-ray crystal structure of the maltooligosaccharide-forming amylase from Bacillus stearothermophilus STB04 (Bst-MFA) with bound acarbose has been determined at 2.2 Å. The structure revealed a classical three-domain fold stabilized by four calcium ions, in which CaI-CaIII form an unprecedented linear metal triad in the interior of domain B. Catalytic residues are deduced to be two aspartic acids and one glutamic acid (Asp234, Glu264, Asp331), and the acarbose is bound to surrounding amino acid residues, mainly through extensive hydrogen bonds. Furthermore, analysis of the structure indicates the existence of at least 8 subsites in Bst-MFA, six glycone sites (-6, -5, -4, -3, -2, -1) and two aglycone sites (+1, +2). Subsite +3 remains to be further explored. Sugar-binding subsites contribute to further presentation of the oligosaccharide-binding mode, which explains the product specificity of Bst-MFA to some extent. In addition, we propose a mechanism by which maltooligosaccharide-forming amylases produce particular maltooligosaccharide products, a result different from that seen with typical α-amylases. Finally, the three-dimensional structure of Bst-MFA complexed with acarbose provides the basis for further studies, designed to increase product specificity. PubMed: 31325505DOI: 10.1016/j.ijbiomac.2019.07.104 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2.2 Å) |
Structure validation
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