3H3K
Structure of A. acidocaldarius cellulase CelA in complex with cellotetraose
Summary for 3H3K
| Entry DOI | 10.2210/pdb3h3k/pdb |
| Related | 3GZK 3H2W |
| Descriptor | Cellulase, beta-D-glucopyranose-(1-4)-beta-D-glucopyranose-(1-4)-beta-D-glucopyranose-(1-4)-alpha-D-glucopyranose, beta-D-glucopyranose, ... (7 entities in total) |
| Functional Keywords | gh9 fold in cazy database, hydrolase, glycosidase |
| Biological source | Alicyclobacillus acidocaldarius (Bacillus acidocaldarius) |
| Total number of polymer chains | 1 |
| Total formula weight | 60219.56 |
| Authors | Morera, S.,Eckert, K. (deposition date: 2009-04-16, release date: 2009-10-13, Last modification date: 2023-11-01) |
| Primary citation | Eckert, K.,Vigouroux, A.,Lo Leggio, L.,Morera, S. Crystal structures of A. acidocaldarius endoglucanase Cel9A in complex with Cello-oligosaccharides: strong -1 and -2 subsites mimic cellobiohydrolase activity J.Mol.Biol., 394:61-70, 2009 Cited by PubMed Abstract: Alicyclobacillus acidocaldarius endoglucanase Cel9A (AaCel9A) is an inverting glycoside hydrolase with beta-1,4-glucanase activity on soluble polymeric substrates. Here, we report three X-ray structures of AaCel9A: a ligand-free structure at 1.8 A resolution and two complexes at 2.66 and 2.1 A resolution, respectively, with cellobiose obtained by co-crystallization and with cellotetraose obtained by the soaking method. AaCel9A forms an (alpha/alpha)(6)-barrel like other glycoside hydrolase family 9 enzymes. When cellobiose is used as a ligand, three glucosyl binding subsites are occupied, including two on the glycone side, while with cellotetraose as a ligand, five subsites, including four on the glycone side, are occupied. A structural comparison showed no conformational rearrangement of AaCel9A upon ligand binding. The structural analysis demonstrates that of the four minus subsites identified, subsites -1 and -2 show the strongest interaction with bound glucose. In conjunction with the open active-site cleft of AaCel9A, this is able to reconcile the previously observed cleavage of short-chain oligosaccharides with cellobiose as main product with the endo mode of action on larger polysaccharides. PubMed: 19729024DOI: 10.1016/j.jmb.2009.08.060 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2.1 Å) |
Structure validation
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