1Q6I

Crystal structure of a truncated form of FkpA from Escherichia coli, in complex with immunosuppressant FK506

Summary for 1Q6I

• Entry DOI: 10.2210/pdb1q6i/pdb
• Related: 1Q6H 1Q6U
• Descriptor: FKBP-type peptidyl-prolyl cis-trans isomerase fkpA, 8-DEETHYL-8-[BUT-3-ENYL]-ASCOMYCIN (3 entities in total)
• Functional Keywords: chaperone, peptidyl-prolyl isomerase, heat shock protein, fkbp family, immunosuppressant fk506, ascomycin, isomerase
• Biological source: Escherichia coli
• Cellular location: Periplasm: P45523
• Total number of polymer chains: 2
• Total formula weight: 50188.24

Authors

Saul, F.A.,Arie, J.-P.,Vulliez-le Normand, B.,Kahn, R.,Betton, J.-M.,Bentley, G.A. (deposition date: 2003-08-13, release date: 2004-01-13, Last modification date: 2024-10-16)

Primary citation

Saul, F.A.,Arie, J.P.,Vulliez-le Normand, B.,Kahn, R.,Betton, J.M.,Bentley, G.A.
Structural and functional studies of FkpA from Escherichia coli, a cis/trans peptidyl-prolyl isomerase with chaperone activity.
J.Mol.Biol., 335:595-608, 2004

PubMed Abstract: The protein FkpA from the periplasm of Escherichia coli exhibits both cis/trans peptidyl-prolyl isomerase (PPIase) and chaperone activities. The crystal structure of the protein has been determined in three different forms: as the full-length native molecule, as a truncated form lacking the last 21 residues, and as the same truncated form in complex with the immunosuppressant ligand, FK506. FkpA is a dimeric molecule in which the 245-residue subunit is divided into two domains. The N-terminal domain includes three helices that are interlaced with those of the other subunit to provide all inter-subunit contacts maintaining the dimeric species. The C-terminal domain, which belongs to the FK506-binding protein (FKBP) family, binds the FK506 ligand. The overall form of the dimer is V-shaped, and the different crystal structures reveal a flexibility in the relative orientation of the two C-terminal domains located at the extremities of the V. The deletion mutant FkpNL, comprising the N-terminal domain only, exists in solution as a mixture of monomeric and dimeric species, and exhibits chaperone activity. By contrast, a deletion mutant comprising the C-terminal domain only is monomeric, and although it shows PPIase activity, it is devoid of chaperone function. These results suggest that the chaperone and catalytic activities reside in the N and C-terminal domains, respectively. Accordingly, the observed mobility of the C-terminal domains of the dimeric molecule could effectively adapt these two independent folding functions of FkpA to polypeptide substrates.

PubMed: 14672666
DOI: 10.1016/j.jmb.2003.10.056

Experimental method

X-RAY DIFFRACTION (2.25 Å)