Pessi A, Bianchi E, Crameri A, Venturini S, Tramontano A, Sollazzo M
Department of Biochemistry, Istituto di Ricerche di Biologia Molecolare P. Angeletti IRBM, Roma, Italy.
Nature. 1993 Mar 25;362(6418):367-9. doi: 10.1038/362367a0.
A major challenge in protein design is to create stable scaffolds into which tailored functions can be introduced. Here we present the design, synthesis and characterization of a 61-residue all-beta protein: the minibody. We used a portion of the heavy chain variable domain of an immunoglobulin as a template, obtaining a molecule with a novel beta-sheet scaffold and two regions corresponding to the hypervariable loops H1 and H2. To exploit the potential for creating functional centres in the minibody, we engineered a metal-binding site into it. This site is formed by one histidine in H1 and two in H2. The protein is folded, compact and able to bind metal, thus representing the first designed beta-protein with a novel fold and a tailored function. By randomizing the sequence of the hypervariable loops, we are using the minibody scaffold to construct a conformationally constrained peptide library displayed on phage.
蛋白质设计中的一个主要挑战是创建能够引入特定功能的稳定支架。在此，我们展示了一种由61个残基组成的全β蛋白——微型抗体的设计、合成及特性。我们以免疫球蛋白重链可变结构域的一部分作为模板，得到了一个具有新型β折叠支架以及对应于高变环H1和H2的两个区域的分子。为了利用在微型抗体中创建功能中心的潜力，我们在其中设计了一个金属结合位点。该位点由H1中的一个组氨酸和H2中的两个组氨酸形成。该蛋白质折叠紧密且能够结合金属，因此代表了首个具有新型折叠和特定功能的设计β蛋白。通过随机化高变环的序列，我们正在利用微型抗体支架构建展示在噬菌体上的构象受限肽库。
