2K2X

Solution Structure of Tick Carboxypeptidase Inhibitor at pH 3.5

2K2X の概要

• エントリーDOI: 10.2210/pdb2k2x/pdb
• 関連するPDBエントリー: 2K2Y 2K2Z
• NMR情報: BMRB: 15729
• 分子名称: Carboxypeptidase inhibitor (1 entity in total)
• 機能のキーワード: tci, blood coagulation, fibrinolysis, metalloenzyme inhibitor, metalloprotease inhibitor, secreted, hydrolase inhibitor
• 由来する生物種: Rhipicephalus bursa (Tick)
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 7945.10

構造登録者

Pantoja-Uceda, D.,Blanco, F. (登録日: 2008-04-15, 公開日: 2009-01-27, 最終更新日: 2024-11-20)

主引用文献

Arolas, J.L.,Pantoja-Uceda, D.,Ventura, S.,Blanco, F.J.,Aviles, F.X.
The NMR structures of the major intermediates of the two-domain tick carboxypeptidase inhibitor reveal symmetry in its folding and unfolding pathways.
J.Biol.Chem., 283:27110-27120, 2008

PubMed Abstract: There is a lack of experimental structural information about folding intermediates of multidomain proteins. Tick carboxypeptidase inhibitor (TCI) is a small, disulfide-rich protein consisting of two domains that fold and unfold autonomously through the formation of two major intermediates, IIIa and IIIb. Each intermediate contains three native disulfide bonds in one domain and six free cysteines in the other domain. Here we have determined the NMR structures of these two intermediates trapped and isolated at acidic pH in which they are stable and compared their structures with that of the native protein analyzed under the same conditions. Both IIIa and IIIb were found to contain a folded region that corresponds to the N- and C-terminal domains of TCI, respectively, with structures very similar to the corresponding regions of the native protein. The remainder of the polypeptide chains of the intermediates was shown to be unfolded in a random coil conformation. Solvent exchange measurements further indicated that the two protein domains are not completely independent, but affect each other in terms of dynamics and stability, in agreement with reported inhibitory activity data. The derived results provide structural evidence for symmetric TCI folding and unfolding mechanisms that converge in IIIa and IIIb and reveal the structural basis that accounts for the strong and simultaneous accumulation of both intermediates. Altogether, this work has important implications for a better understanding of the folding mechanisms of multidomain, disulfide-rich proteins.

PubMed: 18640980
DOI: 10.1074/jbc.M803978200

実験手法

SOLUTION NMR