2p1h
From Proteopedia
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Rapid Folding and Unfolding of Apaf-1 CARD
Overview
Caspase recruitment domains (CARDs) are members of the death domain, superfamily and contain six antiparallel helices in an alpha-helical Greek, key topology. We have examined the equilibrium and kinetic folding of the, CARD of Apaf-1 (apoptotic protease activating factor 1), which consists of, 97 amino acid residues, at pH 6 and pH 8. The results showed that an, apparent two state equilibrium mechanism is not adequate to describe the, folding of Apaf-1 CARD at either pH, suggesting the presence of, intermediates in equilibrium unfolding. Interestingly, the results showed, that the secondary structure is less stable than the tertiary structure, based on the transition mid-points for unfolding. Single mixing and, sequential mixing stopped-flow studies showed that Apaf-1 CARD folds and, unfolds rapidly and suggest a folding mechanism that contains parallel, channels with two unfolded conformations folding to the native, conformation. Kinetic simulations show that a slow folding phase is, described by a third conformation in the unfolded ensemble that, interconverts with one or both unfolded species. Overall, the native, ensemble is formed rapidly upon refolding. This is in contrast to other, CARDs in which folding appears to be dominated by formation of kinetic, traps.
About this Structure
2P1H is a Single protein structure of sequence from Homo sapiens with ZN as ligand. Full crystallographic information is available from OCA.
Reference
Rapid Folding and Unfolding of Apaf-1 CARD., Milam SL, Nicely NI, Feeney B, Mattos C, Clark AC, J Mol Biol. 2007 May 25;369(1):290-304. Epub 2007 Mar 15. PMID:17408690
Page seeded by OCA on Mon Nov 12 23:19:28 2007
Categories: Homo sapiens | Single protein | Clark, A.C. | Feeney, B. | Mattos, C. | Milam, S.L. | Nicely, N.I. | ZN | Apaf-1 | Folding | Unfolding
