3PR9: Structural Analysis Of Protein Folding By The Methanococcus Jannaschii Chaperone Fkbp26

Citation:
Abstract
In the cell, protein folding is mediated by folding catalysts and chaperones. The two functions are often linked, especially when the catalytic module forms part of a multidomain protein, as in Methanococcus jannaschii peptidyl-prolyl cis/trans isomerase FKBP26. Here, we show that FKBP26 chaperone activity requires both a 50-residue insertion in the catalytic FKBP domain, also called 'Insert-in-Flap' or IF domain, and an 80-residue C-terminal domain. We determined FKBP26 structures from four crystal forms and analyzed chaperone domains in light of their ability to mediate protein-protein interactions. FKBP26 is a crescent-shaped homodimer. We reason that folding proteins are bound inside the large crescent cleft, thus enabling their access to inward-facing peptidyl-prolyl cis/trans isomerase catalytic sites and ipsilateral chaperone domain surfaces. As these chaperone surfaces participate extensively in crystal lattice contacts, we speculate that the observed lattice contacts reflect a proclivity for protein associations and represent substrate interactions by FKBP26 chaperone domains. Finally, we find that FKBP26 is an exceptionally flexible molecule, suggesting a mechanism for nonspecific substrate recognition.
PDB ID: 3PR9Download
MMDB ID: 88105
PDB Deposition Date: 2010/11/29
Updated in MMDB: 2011/05
Experimental Method:
x-ray diffraction
Resolution: 1.95  Å
Source Organism:
Similar Structures:
Biological Unit for 3PR9: monomeric; determined by author and by software (PISA)
Molecular Components in 3PR9
Label Count Molecule
Protein (1 molecule)
1
Fkbp-type Peptidyl-prolyl Cis-trans Isomerase(Gene symbol: MJ_RS04410)
Molecule annotation
* Click molecule labels to explore molecular sequence information.

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