The Structural Mechanism for Iron Uptake and Release by Transferrins.
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- HIROSE Masaaki
- The Research Institute for Food Science, Kyoto University
書誌事項
- タイトル別名
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- Structural Mechanism for Iron Uptake and Release by Transferrins
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Transferrins are a group of iron-binding proteins that control the levels of iron in the body fluids of vertebrates by their ability to bind two Fe3+ and two CO32-. The transferrin molecule, with a molecular mass of about 80 kDa, is folded into two similarly sized homologous N- and C-lobes that are stabilized by many intrachain disulfides. As observed by X-ray crystallography, each lobe is further divided into two similarly sized domains, domain 1 and domain 2, and an Fe3+-binding site is within the interdomain cleft. Four of the six Fe3+ coordination sites are occupied by protein ligands (2 Tyr residues, 1 Asp, and 1 His) and the other two by a bidentate CO32-. Upon uptake and release of Fe3+, transferrins undergo a large-scale conformational change dependng on a common structural mechanism: domains 1 and 2 rotate as rigid bodies around a rotation axis that passes through the two antiparallel β-strands linking the domains. The extent of the rotaion is, however, variable for different transferrin species and lobes. As a Fe3+ release mechanisms at low pH from the N-lobes of serum transferrin and ovotransferrin, the structral evidence for ‘dilysine trigger mechanism’ is shown. A structural mechanism for the Fe3+ release in presence of a non-synergistic anion is proposed on the basis of the sulfate-bound apo crystal structure of the ovotransferrin N-lobe. Domain-opened structures with the coordinated Fe3+ by the two tyrosine residues are demonstrated in fragment and intact forms, and their functional implications as a possible intermediate for iron uptake and release are discussed.<br>
収録刊行物
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- Bioscience, Biotechnology, and Biochemistry
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Bioscience, Biotechnology, and Biochemistry 64 (7), 1328-1336, 2000
公益社団法人 日本農芸化学会
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詳細情報 詳細情報について
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- CRID
- 1390001206474221568
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- NII論文ID
- 110002680095
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- NII書誌ID
- AA10824164
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- COI
- 1:CAS:528:DC%2BD3cXlvFGrtb0%3D
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- ISSN
- 13476947
- 09168451
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- NDL書誌ID
- 5475797
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- PubMed
- 10945247
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- 本文言語コード
- en
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- データソース種別
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- JaLC
- NDL
- Crossref
- PubMed
- CiNii Articles
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- 抄録ライセンスフラグ
- 使用不可