1PWT

THERMODYNAMIC ANALYSIS OF ALPHA-SPECTRIN SH3 AND TWO OF ITS CIRCULAR PERMUTANTS WITH DIFFERENT LOOP LENGTHS: DISCERNING THE REASONS FOR RAPID FOLDING IN PROTEINS

1PWT の概要

• エントリーDOI: 10.2210/pdb1pwt/pdb
• 分子名称: ALPHA SPECTRIN (2 entities in total)
• 機能のキーワード: circular permutant, sh3 domain, cytoskeleton
• 由来する生物種: Gallus gallus (chicken)
• 細胞内の位置: Cytoplasm, cytoskeleton: P07751
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 7042.10

構造登録者

Martinez, J.C.,Viguera, A.R.,Berisio, R.,Wilmanns, M.,Mateo, P.L.,Filmonov, V.V.,Serrano, L. (登録日: 1998-10-06, 公開日: 1999-05-11, 最終更新日: 2024-05-22)

主引用文献

Martinez, J.C.,Viguera, A.R.,Berisio, R.,Wilmanns, M.,Mateo, P.L.,Filimonov, V.V.,Serrano, L.
Thermodynamic analysis of alpha-spectrin SH3 and two of its circular permutants with different loop lengths: discerning the reasons for rapid folding in proteins.
Biochemistry, 38:549-559, 1999

PubMed Abstract: The temperature dependences of the unfolding-refolding reaction of a shorter version of the alpha-spectrin SH3 domain (PWT) used as a reference and of two circular permutants (with different poly-Gly loop lengths at the newly created fused loop) have been measured by differential scanning microcalorimetry and stopped-flow kinetics, to characterize the thermodynamic nature of the transition and native states. Differential scanning calorimetry results show that all these species do not belong to the same temperature dependency of heat effect. The family of the N47-D48s circular permutant (with 0-6 Gly inserted at the fused-loop) shows a higher enthalpy as happens with the PWT domain. The wild type (WT) and the S19-P20s permutant family have a more similar behavior although the second is far less stable. The crystallographic structure of the PWT shows a hairpin formation in the region corresponding to the unstructured N-terminus tail of the WT, explaining the enthalpic difference. There is a very good correlation between the calorimetric changes and the structural differences between the WT, PWT, and two circular permutants that suggests that their unfolded state cannot be too different. Elongation of the fused loop in the two permutants, taking as a reference the protein with one inserted Gly, results in a small Gibbs energy change of entropic origin as theoretically expected. Eyring plots of the unfolding and refolding semireactions show different behaviors for PWT, S19-P20s, and N47-D48s in agreement with previous studies indicating that they have different transition states. The SH3 transition state is relatively close to the native state with regard to changes in heat capacity and entropy, indicating a high degree of compactness and order. Regarding the differences in thermodynamic parameters, it seems that rapid folding could be achieved in proteins by decreasing the entropic barrier.

PubMed: 9888794
DOI: 10.1021/bi981515u

実験手法

X-RAY DIFFRACTION (1.77 Å)