5awi | pdb_00005awi

Domain-swapped cytochrome cb562 dimer

spinqualitylabelsall models 5awi, resolution 1.85Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5awi is a 2 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: HEC, SO4, ZN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function C562_ECOLX Electron-transport protein of unknown function. Publication Abstract from PubMed Protein nanostructures have been gaining in interest, along with developments in new methods for construction of novel nanostructures. We have previously shown that c-type cytochromes and myoglobin form oligomers by domain swapping. Herein, we show that a four-helix bundle protein cyt cb(562), with the cyt b(562) heme attached to the protein moiety by two Cys residues insertion, forms a domain-swapped dimer. Dimeric cyt cb(562) did not dissociate to monomers at 4 degrees C, whereas dimeric cyt b(562) dissociated under the same conditions, showing that heme attachment to the protein moiety stabilizes the domain-swapped structure. According to X-ray crystallographic analysis of dimeric cyt cb(562), the two helices in the N-terminal region of one protomer interacted with the other two helices in the C-terminal region of the other protomer, where Lys51-Asp54 served as a hinge loop. The heme coordination structure of the dimer was similar to that of the monomer. In the crystal, three domain-swapped cyt cb(562) dimers formed a unique cage structure with a Zn-SO(4) cluster inside the cavity. The Zn-SO(4) cluster consisted of fifteen Zn(2+) and seven SO(4)(2-) ions, whereas six additional Zn(2+) ions were detected inside the cavity. The cage structure was stabilized by coordination of the amino acid side chains of the dimers to the Zn(2+) ions and connection of two four-helix bundle units through the conformation-adjustable hinge loop. These results show that domain swapping can be applied in the construction of unique protein nanostructures. Domain-swapped cytochrome cb(562) dimer and its nanocage encapsulating a Zn-SO(4) cluster in the internal cavity.,Miyamoto T, Kuribayashi M, Nagao S, Shomura Y, Higuchi Y, Hirota S Chem Sci. 2015 Dec 1;6(12):7336-7342. doi: 10.1039/c5sc02428e. Epub 2015 Sep 22. PMID:28791095 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Cytochrome b5 3D structures

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