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1geq

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

Structural highlights

1geq is a 2 chain structure with sequence from Pyrococcus furiosus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 2Å
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

TRPA_PYRFU The alpha subunit is responsible for the aldol cleavage of indoleglycerol phosphate to indole and glyceraldehyde 3-phosphate.

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

Publication Abstract from PubMed

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.

Entropic stabilization of the tryptophan synthase alpha-subunit from a hyperthermophile, Pyrococcus furiosus. X-ray analysis and calorimetry.,Yamagata Y, Ogasahara K, Hioki Y, Lee SJ, Nakagawa A, Nakamura H, Ishida M, Kuramitsu S, Yutani K J Biol Chem. 2001 Apr 6;276(14):11062-71. Epub 2000 Dec 15. PMID:11118452^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Yamagata Y, Ogasahara K, Hioki Y, Lee SJ, 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. 2001 Apr 6;276(14):11062-71. Epub 2000 Dec 15. PMID:11118452 doi:10.1074/jbc.M009987200