Kossiakoff Anthony A, Koide Shohei
Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, United States.
Curr Opin Struct Biol. 2008 Aug;18(4):499-506. doi: 10.1016/j.sbi.2008.06.004. Epub 2008 Aug 4.
Recent advances in methodologies and design of combinatorial library selection have enabled comprehensive characterization of sequence space for protein-protein interaction interfaces and generation of fully synthetic binding interfaces. By exhaustively introducing and quantitatively analyzing mutations in natural interfaces, new insights into their molecular architecture and plasticity have emerged. Minimalist combinatorial libraries based on a restricted amino acid code have produced synthetic interfaces that rival natural ones using a different set of rules. A two amino acid code composed of just tyrosine and serine in the context of antibody CDR loops is sufficient to produce high affinity and specific interactions with different classes of protein targets. Structural analyses highlight the dominant role of Tyr in forming productive interactions and demonstrate the dominance of conformational diversity over chemical diversity in producing naïve binding interfaces. Synthetic binding proteins are beginning to be used as a powerful crystallization tool to attack important structural biology problems that are recalcitrant to crystallization using traditional methods.
组合文库筛选方法和设计的最新进展，使得对蛋白质-蛋白质相互作用界面的序列空间进行全面表征以及生成完全合成的结合界面成为可能。通过详尽地引入并定量分析天然界面中的突变，人们对其分子结构和可塑性有了新的认识。基于受限氨基酸编码的简约组合文库产生了能与天然界面相媲美的合成界面，只是运用了不同的规则。在抗体互补决定区（CDR）环的背景下，仅由酪氨酸和丝氨酸组成的双氨基酸编码就足以与不同类别的蛋白质靶标产生高亲和力和特异性相互作用。结构分析突出了酪氨酸在形成有效相互作用中的主导作用，并证明了在产生原始结合界面时构象多样性比化学多样性更为重要。合成结合蛋白正开始被用作一种强大的结晶工具，以攻克使用传统方法难以结晶的重要结构生物学问题。
