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

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)
Fkbp-type Peptidyl-prolyl Cis-trans Isomerase(Gene symbol: MJ_RS04410)
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB