Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford OX1 3TA, UK.
Curr Opin Chem Biol. 2010 Dec;14(6):781-9. doi: 10.1016/j.cbpa.2010.10.007.
The ability to alter protein structure by site-directed mutagenesis has revolutionized biochemical research. Controlled mutations at the DNA level, before protein translation, are now routine. These techniques allow specific, high fidelity interconversion largely between 20 natural, proteinogenic amino acids. Nonetheless, there is a need to incorporate other amino acids, both natural and unnatural, that are not accessible using standard site-directed mutagenesis and expression systems. Post-translational chemistry offers access to these side chains. Nearly half a century ago, the idea of a 'chemical mutation' was proposed and the interconversion between amino acid side chains was demonstrated on select proteins. In these isolated examples, a powerful proof-of-concept was demonstrated. Here, we revive the idea of chemical mutagenesis and discuss the prospect of its general application in protein science. In particular, we consider amino acids that are chemical precursors to a functional set of other side chains. Among these, dehydroalanine has much potential. There are multiple methods available for dehydroalanine incorporation into proteins and this residue is an acceptor for a variety of nucleophiles. When used in conjunction with standard genetic techniques, chemical mutagenesis may allow access to natural, modified, and unnatural amino residues on translated, folded proteins.
通过定点突变改变蛋白质结构的能力使生化研究发生了革命性的变化。在蛋白质翻译之前，在 DNA 水平上进行受控突变现在已成为常规操作。这些技术允许在很大程度上在 20 种天然的、蛋白质源的氨基酸之间进行特定的、高保真的相互转换。尽管如此，仍然需要引入其他氨基酸，包括天然和非天然氨基酸，而这些氨基酸无法通过标准的定点突变和表达系统获得。翻译后化学为这些侧链提供了途径。近半个世纪前，人们提出了“化学突变”的想法，并在一些特定蛋白质上证明了氨基酸侧链之间的相互转换。在这些孤立的例子中，展示了一个强有力的概念验证。在这里，我们重新审视化学诱变的想法，并讨论其在蛋白质科学中的广泛应用前景。特别是，我们考虑了那些是其他功能侧链化学前体的氨基酸。其中，脱氢丙氨酸具有很大的潜力。有多种方法可将脱氢丙氨酸掺入蛋白质中，并且该残基是多种亲核试剂的受体。当与标准遗传技术结合使用时，化学诱变可能会允许在翻译、折叠的蛋白质上引入天然、修饰和非天然的氨基酸残基。
