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Stabilization mechanism of the tryptophan synthase alpha-subunit from Thermus thermophilus HB8: X-ray crystallographic analysis and calorimetry.
J Biochem. 2005 Oct; 138(4):343-53.JB

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.

Authors+Show Affiliations

Advanced Protein Crystallography Research Group, RIKEN Harima Institute at SPring-8, 1-1-1 Kouto, Mikazuki-cho, Sayo-gun, Hyogo 679-5148.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

16272128

Citation

Asada, Yukuhiko, et al. "Stabilization Mechanism of the Tryptophan Synthase Alpha-subunit From Thermus Thermophilus HB8: X-ray Crystallographic Analysis and Calorimetry." Journal of Biochemistry, vol. 138, no. 4, 2005, pp. 343-53.
Asada Y, Sawano M, Ogasahara K, et al. Stabilization mechanism of the tryptophan synthase alpha-subunit from Thermus thermophilus HB8: X-ray crystallographic analysis and calorimetry. J Biochem. 2005;138(4):343-53.
Asada, Y., Sawano, M., Ogasahara, K., Nakamura, J., Ota, M., Kuroishi, C., Sugahara, M., Yutani, K., & Kunishima, N. (2005). Stabilization mechanism of the tryptophan synthase alpha-subunit from Thermus thermophilus HB8: X-ray crystallographic analysis and calorimetry. Journal of Biochemistry, 138(4), 343-53.
Asada Y, et al. Stabilization Mechanism of the Tryptophan Synthase Alpha-subunit From Thermus Thermophilus HB8: X-ray Crystallographic Analysis and Calorimetry. J Biochem. 2005;138(4):343-53. PubMed PMID: 16272128.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Stabilization mechanism of the tryptophan synthase alpha-subunit from Thermus thermophilus HB8: X-ray crystallographic analysis and calorimetry. AU - Asada,Yukuhiko, AU - Sawano,Masahide, AU - Ogasahara,Kyoko, AU - Nakamura,Junji, AU - Ota,Motonori, AU - Kuroishi,Chizu, AU - Sugahara,Mitsuaki, AU - Yutani,Katsuhide, AU - Kunishima,Naoki, PY - 2005/11/8/pubmed PY - 2006/3/11/medline PY - 2005/11/8/entrez SP - 343 EP - 53 JF - Journal of biochemistry JO - J Biochem VL - 138 IS - 4 N2 - 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. SN - 0021-924X UR - https://www.unboundmedicine.com/medline/citation/16272128/Stabilization_mechanism_of_the_tryptophan_synthase_alpha_subunit_from_Thermus_thermophilus_HB8:_X_ray_crystallographic_analysis_and_calorimetry_ DB - PRIME DP - Unbound Medicine ER -