3tco

Crystallographic and spectroscopic characterization of Sulfolobus solfataricus TrxA1 provide insights into the determinants of thioredoxin fold stability

spinqualitylabelsall models 3tco, resolution 1.90Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3tco is a 3 chain structure with sequence from Saccharolobus solfataricus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.9Å Ligands: EDO Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q980E5_SACS2 Publication Abstract from PubMed Structural characterizations of thioredoxins (Trxs) are important for their involvement in severe pathologies and for their stable scaffold. Here we report a combined structural and spectroscopic characterization of a Trx isolated from the hyperthermophilic archaeon Sulfolobus solfataricus (SsTrxA1). Thermal denaturation unveils that SsTrxA1 is endowed with a remarkable stability in the explored temperature range 50-105 degrees C. The structure of the oxidized form of SsTrxA1 determined at 1.9A resolution presents a number of peculiar features. Although the protein was crystallized in a slightly acid medium (pH 6.5) as many as ten intramolecular/intermolecular carboxyl-carboxylate interactions involving glutamic and aspartic acid side chains are found in three independent SsTrxA1 molecules present in the asymmetric unit. Surprisingly for a hyperthermostable protein, the structure of SsTrxA1 is characterized by the presence (a) of a very limited number of intramolecular salt bridges and (b) of a cavity nearby Cys52, a residue that is frequently a phenylananine in other members of the family. Chemical denaturation investigations carried out on SsTrxA1 and SsTrxA2 show that both proteins present a significant stability against guanidine hydrochloride, thus indicating that ionic interactions play a minor role in their stabilization. Compared to Trxs from mesophilic sources, SsTrxA1 displays a longer alpha-helix 1 and a shorter loop connecting this alpha-helix with beta-strand 2. As these features are shared with Trxs isolated from thermophilic sources, the shortening of this loop may be a general strategy adopted to stabilize this fold. This feature may be exploited for the design of hyperthermostable Trx scaffolds. Crystallographic and spectroscopic characterizations of Sulfolobus solfataricus TrxA1 provide insights into the determinants of thioredoxin fold stability.,Esposito L, Ruggiero A, Masullo M, Ruocco MR, Lamberti A, Arcari P, Zagari A, Vitagliano L J Struct Biol. 2011 Nov 7. PMID:22085748 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Thioredoxin 3D structures

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