A hemoglobin-like protein from Protozoan ciliates : Its structure and function

原生动物纤毛虫的血红蛋白样蛋白：其结构和功能

• 批准号: 07640896
• 负责人: SHIKWA Kenji
• 金额: $ 1.41万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1996
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07640896/
• 关键词: Hemoglobin; Myoglobin; Protozoa; Ciliates; Paramecium; Tetrahymena; Autoxidation; Molecular evolution; 絨毛虫類; シオグロビン

A myoglobin-like protein from Tetrahymena pyriformis is composed of 121 amino acid residues with a molecular mass of 14,343 daltons including the heme moiety. This is much smaller than sperm whale myoglobin by 32 residues and shows no notable degree of sequence similarity with other myoglobins and hemoglobins. In order to examine this unique protein for its spectral and stability properties, we have isolated a large amount of its native oxy-form directly from the packed cells by using gel filtration on Sephadex G-50 followed by CM-cellulose chromatography. As a result, Tetrahymena oxymyoglobin was found to be quite resistant against the autoxidation reaction over a wide range of pH4-12 in 0.1M buffer at 25ﾟC,its rate-constant being almost the same as that of sperm whale MbO_2. We therefore conclude that Tetrahymena myoglobin can bind molecular oxygen as stably as mammalian myoglobins can do, in spite of its very contracted structure probably due to a large number of amino acid deletions.

来自梨形四膜虫的肌红蛋白样蛋白由121个氨基酸残基组成，分子量为14，343道尔顿，包括血红素部分。这比抹香鲸肌红蛋白小32个残基，并且与其他肌红蛋白和血红蛋白没有显着的序列相似性。为了研究这种独特的蛋白质的光谱和稳定性，我们已经分离了大量的天然氧形式直接从压缩细胞通过使用凝胶过滤Sephadex G-50，然后CM-纤维素色谱。结果表明，四膜虫氧合肌红蛋白在25 ℃、0.1M缓冲液中，在pH 4 -12的范围内对自氧化反应有很强的抵抗力，其速率常数与抹香鲸的MbO_2几乎相同。因此，我们得出结论，四膜虫肌红蛋白可以结合分子氧稳定的哺乳动物肌红蛋白可以做，尽管其非常收缩的结构可能是由于大量的氨基酸缺失。

项目成果

四釜 慶治: "新タンパク質応用工学(分担執筆)" 下等生物にみられるヘモグロビン様タンパク質の構造と機能, 950 (1996)

Keiji Shigama：“新蛋白质应用工程（合著者）”低等生物中发现的血红蛋白样蛋白质的结构和功能，950（1996）

Korenaga, S.et al.: "A Myoglobin-like Protein from Tetrahymena pyriformis : Isolation and Characterization." Europ.J.Protistol. 32. 73-78 (1996)

Korenaga, S.et al.：“来自梨形四膜虫的肌红蛋白样蛋白：分离和表征。”

四釜慶治: "単細胞生物にみられるヘモグロビン様タンパク質-ゾウリムシのMbと酵母のHb-" 生物物理. 35. 13-18 (1995)

Keiji Shikama：“单细胞生物中发现的血红蛋白样蛋白 - 草履虫中的 Mb 和酵母中的 Hb”《生物物理学》35. 13-18 (1995)。

Matsuoka,A.et al.: "The Dimer-Monomer Conversion of Cerithidea Myoglobin Coupled with the Heme Iron Oxidation." Comp.Biochem.Physiol.115B. 483-492 (1996)

Matsuoka,A.et al.：“Cerithidea 肌红蛋白的二聚体-单体转化与血红素铁氧化相结合。”

Tsuruga, M.et al.: "Biphasic nature in the autoxidation reaction of human oxyhemoglobin." Biochim.Biophys.Acta. (in press). (1996)

Tsuruga, M.et al.：“人氧合血红蛋白自氧化反应的双相性质。”