3QDQ
Complex between 4-hydroxybutyrate CoA-transferase from Clostridium aminobutyricum and CoA
Summary for 3QDQ
| Entry DOI | 10.2210/pdb3qdq/pdb |
| Related | 3GK7 |
| Descriptor | 4-Hydroxybutyrate CoA-transferase, COENZYME A (3 entities in total) |
| Functional Keywords | coa transferase family i; single subunit coa transferase, coa, transferase |
| Biological source | Clostridium aminobutyricum |
| Total number of polymer chains | 1 |
| Total formula weight | 49724.57 |
| Authors | Messerschmidt, A.,Macieira, S. (deposition date: 2011-01-19, release date: 2011-08-24, Last modification date: 2023-09-13) |
| Primary citation | Macieira, S.,Zhang, J.,Buckel, W.,Messerschmidt, A. Crystal structure of the complex between 4-hydroxybutyrate CoA-transferase from Clostridium aminobutyricum and CoA. Arch.Microbiol., 194:157-166, 2012 Cited by PubMed Abstract: Clostridium aminobutyricum ferments 4-aminobutyrate (γ-aminobutyrate, GABA) to ammonia, acetate and butyrate via 4-hydroxybutyrate that is activated to the CoA-thioester catalyzed by 4-hydroxybutyrate CoA-transferase. Then, 4-hydroxybutyryl-CoA is dehydrated to crotonyl-CoA, which disproportionates to butyryl-CoA and acetyl-CoA. Cocrystallization of the CoA-transferase with the alternate substrate butyryl-CoA yielded crystals with non-covalently bound CoA and two water molecules at the active site. Most likely, butyryl-CoA reacted with the active site Glu238 to CoA and the mixed anhydride, which slowly hydrolyzed during crystallization. The structure of the CoA is similar but less stretched than that of the CoA-moiety of the covalent enzyme-CoA-thioester in 4-hydroxybutyrate CoA-transferase from Shewanella oneidensis. In contrast to the structures of the apo-enzyme and enzyme-CoA-thioester, the structure described here has a closed conformation, probably caused by a flip of the active site loop (residues 215-219). During turnover, the closed conformation may protect the anhydride intermediate from hydrolysis and CoA from dissociation from the enzyme. Hence, one catalytic cycle changes conformation of the enzyme four times: free enzyme-open conformation, CoA+ anhydride 1-closed, enzyme-CoA-thioester-open, CoA + anhydride-2-closed, free enzyme-open. PubMed: 21833509DOI: 10.1007/s00203-011-0737-2 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2.6 Å) |
Structure validation
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