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| == Function == | | == Function == |
| [https://www.uniprot.org/uniprot/C562_ECOLX C562_ECOLX] Electron-transport protein of unknown function. | | [https://www.uniprot.org/uniprot/C562_ECOLX C562_ECOLX] Electron-transport protein of unknown function. |
| <div style="background-color:#fffaf0;">
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| == Publication Abstract from PubMed ==
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| 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.
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| 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<ref>PMID:28791095</ref>
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| From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br>
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| </div>
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| <div class="pdbe-citations 5awi" style="background-color:#fffaf0;"></div>
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| ==See Also== | | ==See Also== |
| *[[Cytochrome b5 3D structures|Cytochrome b5 3D structures]] | | *[[Cytochrome b5 3D structures|Cytochrome b5 3D structures]] |
| == References ==
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| <references/>
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| __TOC__ | | __TOC__ |
| </StructureSection> | | </StructureSection> |
