1UJP
Crystal Structure of Tryptophan Synthase A-Subunit From Thermus thermophilus HB8
Summary for 1UJP
| Entry DOI | 10.2210/pdb1ujp/pdb |
| Descriptor | Tryptophan synthase alpha chain, CITRIC ACID (3 entities in total) |
| Functional Keywords | tryptophan synthase, tryptophan, riken structural genomics/proteomics initiative, rsgi, structural genomics, lyase |
| Biological source | Thermus thermophilus |
| Total number of polymer chains | 1 |
| Total formula weight | 29169.65 |
| Authors | Asada, Y.,Yokoyama, S.,Kuramitsu, S.,Miyano, M.,Kunishima, N.,RIKEN Structural Genomics/Proteomics Initiative (RSGI) (deposition date: 2003-08-08, release date: 2003-08-26, Last modification date: 2023-10-25) |
| Primary citation | Asada, Y.,Sawano, M.,Ogasahara, K.,Nakamura, J.,Ota, M.,Kuroishi, C.,Sugahara, M.,Yutani, K.,Kunishima, N. Stabilization mechanism of the tryptophan synthase alpha-subunit from Thermus thermophilus HB8: X-ray crystallographic analysis and calorimetry. J.Biochem.(Tokyo), 138:343-353, 2005 Cited by PubMed Abstract: In order to elucidate the thermo-stabilization mechanism of the tryptophan synthase alpha-subunit from the extreme thermophile Thermus thermophilus HB8 (Tt-alpha-subunit), its crystal structure was determined and its stability was examined using DSC. The results were compared to those of other orthologs from mesophilic and hyperthermophilic organisms. The denaturation temperature of the Tt-alpha-subunit was higher than that of the alpha-subunit from S. typhimurium (St-alpha-subunit) but lower than that of the alpha-subunit from P. furiosus (Pf-alpha-subunit). Specific denaturation enthalpy and specific denaturation heat capacity values of the Tt-alpha-subunit were the lowest among the three proteins, suggesting that entropy effects are responsible for the stabilization of the Tt-alpha-subunit. Based on a structural comparison with the St-alpha-subunit, two deletions in loop regions, an increase in the number of ion pairs and a decrease in cavity volume seem to be responsible for the stabilization of the Tt-alpha-subunit. The results of structural comparison suggest that the native structure of the Tt-alpha-subunit is better adapted to an ideally stable structure than that of the St-alpha-subunit, but worse than that of the Pf-alpha-subunit. The results of calorimetry suggest that the residual structure of the Tt-alpha-subunit in the denatured state contributes to the stabilization. PubMed: 16272128DOI: 10.1093/jb/mvi133 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.34 Å) |
Structure validation
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