The emergence of new therapeutic modalities requires complementary tools for their efficient syntheses. Availability of methodologies for site-selective modification of biomolecules remains a long-standing challenge, given the inherent complexity and the presence of repeating residues that bear functional groups with similar reactivity profiles. We describe a bioconjugation strategy for modification of native peptides relying on high site selectivity conveyed by enzymes. We engineered penicillin G acylases to distinguish among free amino moieties of insulin (two at amino termini and an internal lysine) and manipulate cleavable phenylacetamide groups in a programmable manner to form protected insulin derivatives. This enables selective and specific chemical ligation to synthesize homogeneous bioconjugates, improving yield and purity compared to the existing methods, and generally opens avenues in the functionalization of native proteins to access biological probes or drugs.

中文翻译：

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天然肽和蛋白质位点选择性功能化的化学酶策略

新治疗方式的出现需要补充工具来有效合成它们。鉴于固有的复杂性和具有相似反应性特征的官能团的重复残基的存在，生物分子的位点选择性修饰方法的可用性仍然是一个长期的挑战。我们描述了一种依赖酶传递的高位点选择性修饰天然肽的生物共轭策略。我们设计了青霉素 G 酰基转移酶以区分胰岛素的游离氨基部分（两个在氨基末端和一个内部赖氨酸），并以可编程方式操纵可切割的苯乙酰胺基团以形成受保护的胰岛素衍生物。这使得选择性和特异性化学连接能够合成均质的生物偶联物，