Contribution of heme-propionate side chains to structure and function of myoglobin: chemical approach by artificially created prosthetic groups

Takashi Hayashi, Takashi Matsuo, Yutaka Hitomi, Kazufumi Okawa, Akihiro Suzuki, Yoshitsugu Shiro, Tetsutaro Iizuka, Yoshio Hisaeda, Hisanobu Ogoshi

    研究成果: ジャーナルへの寄稿学術誌査読

    27 被引用数 (Scopus)

    抄録

    Horse heart myoglobin was reconstituted with mesohemin derivatives methylated at the 6- or 7-position to evaluate the role of the heme-6-propionate or heme-7-propionate side chain in the protein. The association and dissociation of the O2 binding for the deoxymyoglobin with 6-methyl-7-propionate mesoheme are clearly accelerated. Furthermore, the myoglobin with 6-methyl-7-propionate mesoheme shows fast autoxidation from oxymyoglobin to metmyoglobin compared to the myoglobin with 6-propionate-7-methyl heme and the reference protein. These results indicate the 6-propionate plays an important physiological role in the stabilization of oxymyoglobin because of the formation of a salt-bridge with the Lys45. The acceleration of CO binding rate is observed for the myoglobin with 6-propionate-7-methyl mesoheme, suggesting that the replacement of the 7-propionate with a methyl group has an influence on the His93-heme iron coordination. The structural perturbation of His93 imidazole was also supported by 1H NMR spectra of cyanide and deoxy forms of the myoglobin with 6-propionate-7-methyl mesoheme. Thus, it is found that the 7-propionate regulates the hydrogen-bonding network and His93-heme iron coordination in the proximal site.

    本文言語英語
    ページ(範囲)94-100
    ページ数7
    ジャーナルJournal of inorganic biochemistry
    91
    1
    DOI
    出版ステータス出版済み - 7月 25 2002

    !!!All Science Journal Classification (ASJC) codes

    • 生化学
    • 無機化学

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