Modulation of function in a minimalist heme-binding membrane protein
Modulation of function in a minimalist heme-binding membrane protein
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极简血红素结合膜蛋白的功能调节
DOI：
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
G. Ghirlanda
中科院分区：
文献类型：
--
作者：
S. Shinde;Jeanine M. Cordova;Brian W. Woodrum;G. Ghirlanda
从头设计的血红素结合蛋白已成功地用于概括天然血红素蛋白的特征。这种方法现在已经扩展到膜可溶性模型蛋白。我们的小组通过将双组氨酸结合位点工程化到天然膜蛋白血型糖蛋白A中来设计功能性血红素蛋白ME 1（Cordova等人，J Am Chem Soc 129：512-518，2007）。ME 1以亚微摩尔亲和力结合铁（III）原卟啉IX，氧化还原电位为−128 mV，并显示过氧化物酶活性。在这里，我们展示了芳香族残基在膜可溶性模型系统的背景下调节氧化还原电位的效果。我们通过单点突变体G25 F设计了与血红素的芳香族相互作用，其中苯丙氨酸被设计为对接卟啉环。这种突变导致与铁（III）原卟啉IX（Kd，app = 6.5 × 10−8 M）的结合紧密了大约10倍，并将辅因子的氧化还原电位降低到−172 mV。这项工作表明，可以在极简主义膜血红蛋白模型中引入旨在控制结合辅因子性质的特定设计特征。调节嵌入人工膜蛋白中的辅因子的氧化还原电位的能力对于功能光合装置中跨膜电子传递链的设计至关重要。
De novo designed heme-binding proteins have been used successfully to recapitulate features of natural hemoproteins. This approach has now been extended to membrane-soluble model proteins. Our group designed a functional hemoprotein, ME1, by engineering a bishistidine binding site into a natural membrane protein, glycophorin A (Cordova et al. in J Am Chem Soc 129:512–518, 2007). ME1 binds iron(III) protoporphyrin IX with submicromolar affinity, has a redox potential of −128 mV, and displays peroxidase activity. Here, we show the effect of aromatic residues in modulating the redox potential in the context of a membrane-soluble model system. We designed aromatic interactions with the heme through a single-point mutant, G25F, in which a phenylalanine is designed to dock against the porphyrin ring. This mutation results in roughly tenfold tighter binding to iron(III) protoporphyrin IX (Kd,app = 6.5 × 10−8 M), and lowers the redox potential of the cofactor to −172 mV. This work demonstrates that specific design features aimed at controlling the properties of bound cofactors can be introduced in a minimalist membrane hemoprotein model. The ability to modulate the redox potential of cofactors embedded in artificial membrane proteins is crucial for the design of electron transfer chains across membranes in functional photosynthetic devices.
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影响因子：
15
作者：
Ghirlanda, G;Osyczka, A;DeGrado, WF
通讯作者：
DeGrado, WF
影响因子：
4.6
作者：
Yatsunyk, Liliya A.;Dawson, Alice;Walker, F. Ann
通讯作者：
Walker, F. Ann
影响因子：
4.6
作者：
Huffman, DL;Suslick, KS
通讯作者：
Suslick, KS
影响因子：
15
作者：
Korendovych IV;Senes A;Kim YH;Lear JD;Fry HC;Therien MJ;Blasie JK;Walker FA;Degrado WF
通讯作者：
Degrado WF
影响因子：
2.9
作者：
Discher, BM;Noy, D;Dutton, PL
通讯作者：
Dutton, PL