1GEQ

Entropic stabilization of the tryptophan synthase A-subunit from a hyperthermophile, pyrococcus furiosus: X-ray analysis and calorimetry

1GEQ の概要

• エントリーDOI: 10.2210/pdb1geq/pdb
• 分子名称: TRYPTOPHAN SYNTHASE ALPHA-SUBUNIT (2 entities in total)
• 機能のキーワード: tryptophan synthase alpha-subunit, hyperthermophile, pyrococcus furiosus, x-ray analysis, stability, calorimetry, lyase
• 由来する生物種: Pyrococcus furiosus
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 55071.69

構造登録者

Yutani, K.,Yamagata, Y. (登録日: 2000-11-21, 公開日: 2000-12-13, 最終更新日: 2023-12-27)

主引用文献

Yamagata, Y.,Ogasahara, K.,Hioki, Y.,Lee, S.J.,Nakagawa, A.,Nakamura, H.,Ishida, M.,Kuramitsu, S.,Yutani, K.
Entropic stabilization of the tryptophan synthase alpha-subunit from a hyperthermophile, Pyrococcus furiosus. X-ray analysis and calorimetry.
J.Biol.Chem., 276:11062-11071, 2001

PubMed Abstract: The structure of the tryptophan synthase alpha-subunit from Pyrococcus furiosus was determined by x-ray analysis at 2.0-A resolution, and its stability was examined by differential scanning calorimetry. Although the structure of the tryptophan synthase alpha(2)beta(2) complex from Salmonella typhimurium has been already determined, this is the first report of the structure of the alpha-subunit alone. The alpha-subunit from P. furiosus (Pf-alpha-subunit) lacked 12 and 6 residues at the N and C termini, respectively, and one residue each in two loop regions as compared with that from S. typhimurium (St-alpha-subunit), resulting in the absence of an N-terminal helix and the shortening of a C-terminal helix. The structure of the Pf-alpha-subunit was essentially similar to that of the St-alpha-subunit in the alpha(2)beta(2) complex. The differences between both structures were discussed in connection with the higher stability of the Pf-alpha-subunit and the complex formation of the alpha- and beta-subunits. Calorimetric results indicated that the Pf-alpha-subunit has extremely high thermostability and that its higher stability is caused by an entropic effect. On the basis of structural information of both proteins, we analyzed the contributions of each stabilization factor and could conclude that hydrophobic interactions in the protein interior do not contribute to the higher stability of the Pf-alpha-subunit. Rather, the increase in ion pairs, decrease in cavity volume, and entropic effects due to shortening of the polypeptide chain play important roles in extremely high stability in Pf-alpha-subunit.

PubMed: 11118452
DOI: 10.1074/jbc.M009987200

実験手法

X-RAY DIFFRACTION (2 Å)