Construction of a Triangle‐Shaped Trimer and a Tetrahedron Using an α‐Helix‐Inserted Circular Permutant of Cytochrome c555 |
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| Authors: | Akiya Oda Dr. Satoshi Nagao Dr. Masaru Yamanaka Ikki Ueda Dr. Hiroki Watanabe Prof. Dr. Takayuki Uchihashi Dr. Naoki Shibata Prof. Dr. Yoshiki Higuchi Prof. Dr. Shun Hirota |
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| Affiliation: | 1. Graduate School of Materials Science, Nara Institute of Science and Technology, Ikoma, Nara, Japan;2. Department of Physics, Nagoya University, Nagoya, Aichi, Japan;3. Department of Life Science, Graduate School of Life Science, University of Hyogo, Kamigori-cho, Ako-gun, Hyogo, Japan;4. RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan |
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| Abstract: | Highly‐ordered protein structures have gained interest for future uses for biomaterials. Herein, we constructed a building block protein (BBP) by the circular permutation of the hyperthermostable Aquifex aeolicus cytochrome (cyt) c555, and assembled BBP into a triangle‐shaped trimer and a tetrahedron. The angle of the intermolecular interactions of BBP was controlled by cleaving the domain‐swapping hinge loop of cyt c555 and connecting the original N‐ and C‐terminal α‐helices with an α‐helical linker. We obtained BBP oligomers up to ≈40 mers, with a relatively large amount of trimers. According to the X‐ray crystallographic analysis of the BBP trimer, the N‐terminal region of one BBP molecule interacted intermolecularly with the C‐terminal region of another BBP molecule, resulting in a triangle‐shaped structure with an edge length of 68 Å. Additionally, four trimers assembled into a unique tetrahedron in the crystal. These results demonstrate that the circular permutation connecting the original N‐ and C‐terminal α‐helices with an α‐helical linker may be useful for constructing organized protein structures. |
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| Keywords: | circular permutation cytochrome c555 protein design protein oligomers protein structures |
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