シトクロム<i>c</i>ポリマー：水溶性球状タンパク質に見出された多量化機構

• 廣田 俊

  奈良先端科学技術大学院大学物質創成科学研究科

• 樋口 芳樹

  兵庫県立大学大学院生命理学研究科

書誌事項

タイトル別名

• Cytochrome <i>c</i> Polymer: Polymerization Mechanism Discovered in a Water-soluble Globular Protein
• シトクロム cポリマー : スイヨウセイ キュウジョウ タンパクシツ ニ ミイダサレタ タリョウカ キコウ

抄録

Cytochrome c (cyt c) is a stable globular protein which functions in a monomeric state as an electron donor for cytochrome c oxidase. It is also released to the cytosol when permeabilization of the mitochondrial outer membrane occurs at the early stage of apoptosis. For half a century, it has been known that cyt c forms polymers, but the polymerization mechanism remains unknown. In the crystal structures of dimeric and trimeric cyt c, the C-terminal helices are replaced by the corresponding domain of other cyt c molecules and Met80 is dissociated from the heme. The solution structures of dimeric, trimeric, and tetrameric cyt c were linear based on small-angle X-ray scattering measurements, where the trimeric linear structure shifted toward the cyclic structure by addition of PEG and (NH₄)₂HPO₄. The absorption and CD spectra of high order oligomers (∼40 mer) were similar to those of dimeric and trimeric cyt c but different from those of monomeric cyt c. These results show that cyt c forms polymers by successive domain swapping, where the C-terminal helix is displaced from its original position in the monomer and Met-heme coordination is perturbed significantly. Successive domain swapping may be a common mechanism of protein polymerization.

収録刊行物

• 日本結晶学会誌

  日本結晶学会誌 54 (5), 270-275, 2012

  日本結晶学会

詳細情報

• CRID: 1390001204088306816
• NII論文ID: 10031129961
• NII書誌ID: AN00188364
• DOI: 10.5940/jcrsj.54.270
• ISSN: 18845576
• ISSN: 03694585
• NDL書誌ID: 024085155
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I024085155
• 本文言語コード: ja
• データソース種別:
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