1q6h
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| , resolution 1.97Å | |||||||
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| Ligands: | |||||||
| Gene: | FKPA OR B3347 (Escherichia coli) | ||||||
| Activity: | Peptidylprolyl isomerase, with EC number 5.2.1.8 | ||||||
| Related: | 1Q6I, 1Q6U
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| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
Crystal structure of a truncated form of FkpA from Escherichia coli
OverviewOverview
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.
About this StructureAbout this Structure
1Q6H is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
ReferenceReference
Structural and functional studies of FkpA from Escherichia coli, a cis/trans peptidyl-prolyl isomerase with chaperone activity., Saul FA, Arie JP, Vulliez-le Normand B, Kahn R, Betton JM, Bentley GA, J Mol Biol. 2004 Jan 9;335(2):595-608. PMID:14672666
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