We present a method for tyrosine-selective and reversible bioconjugation; tyrosines are enzymatically converted into catechols and in situ “clicked” onto boronic acids. Importantly, our process selectively produces catechols and avoids quinones, thereby improving the control over the chemical identity of the products. We have conjugated boronic acid-containing hyaluronic acid (HyA) to peptides bearing tyrosines in variable number and position; the use of tagging peptides for the provision of well exposed tyrosine residues—in our case the hemagglutinin-derived HA-tag—makes our approach applicable to virtually any protein; we have demonstrated this concept by conjugating HA-tagged ovalbumin to HyA, thereby also showing the feasibility of producing chimeric proteoglycans. A caveat of this appproach is that, although the formation of boronic esters does not affect the biological recognition of substrates (ovalbumin and HyA), the introduction of catechols may alter some of their biological properties: for example, only after tyrosinase treatment ovalbumin directly induced dendritic cell maturation, either alone or as a HyA conjugate.

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酪氨酸酶介导的生物缀合。嵌合高分子的多功能方法

我们提出了一种酪氨酸选择性和可逆生物结合的方法。酪氨酸被酶催化转化为儿茶酚，并就地“点击”到硼酸上。重要的是，我们的工艺选择性地生产了邻苯二酚并避免了醌，从而提高了对产品化学特性的控制。我们已经将含硼酸的透明质酸（HyA）与具有可变数目和位置的酪氨酸的肽缀合。使用标签肽提供充分暴露的酪氨酸残基（在我们的情况下是血凝素来源的HA标签）使我们的方法几乎适用于任何蛋白质；我们已经通过将HA标记的卵清蛋白与HyA偶联来证明了这一概念，从而也显示了生产嵌合蛋白聚糖的可行性。此方法的一个警告是，