Nativelike Structure in Designed Four -Helix Bundles Driven by Buried Polar Interactions
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- 作者：Ronald L. Koder ; Kathleen G. Valentine ; Jose Cerda ; Dror Noy ; Kevin M. Smith ; A. Joshua Wand ; P. Leslie Dutton
- 刊名：Journal of the American Chemical Society
- 出版年：2006
- 出版时间：November 15, 2006
- 年：2006
- 卷：128
- 期：45
- 页码：14450 - 14451
- 全文大小：103K
- 年卷期：v.128,no.45(November 15, 2006)
- ISSN：1520-5126
文摘
We show that a single internal polar interaction per helix is sufficient to engender structural specificity in that helix in helical bundle proteins. Furthermore, we use histidine-binding cofactors of different shapes which bind directly into the core, demonstrating that this structural specificity is not the result of a prescribed complimentary, "knobs in holes" core packing. We show that we can switch structural specificity of individual helices on and off by ligating cofactors, singly and in pairs, which bind either one or two histidine ligands. To our knowledge, this is the first demonstration of such extensive manipulation of protein structure by ligand binding, an important result of general interest to those working with self-assembled molecular systems. Finally, as these proteins were designed without the use of computational modeling, we not only demonstrate that designing a uniquely structured cofactor binding protein is not as difficult as is generally believed, we have determined why this is so: hydrophobic core complementarity, which is very difficult to design, is not necessary. Instead, a much simpler design process entails the creation of core polar interactions which themselves can drive conformational specificity.