Chemical tools can provide unique insights into biomolecule structure and function. Included in this group are bioorthogonal chemical reporters?biocompatible functional groups that can target diverse classes of biomolecules and be selectively ligated with various probes. These reporters and reactions enable biomolecules to be analyzed in their native environments. Despite their past successes and continued potential, most chemical reporters have been slow to transition to biological studies and the scientific community at large. Many reporters are too large or insufficiently stable for routine cellular use, or lack chemical versatility. The long-term goal of our work is to develop robust, easy-to-access chemical probes for tracking and controlling biomolecules in cells and tissues. The objective of this application is to develop one reagent?cyclopropenone?as a general and versatile chemical reporter. Cyclopropenones harbor unique features for biological application. They are small, reactive with bioorthogonal soft nucleophiles (e.g., phosphines), and highly tunable. In addition to tagging biomolecules, cyclopropenones can be used to control biomolecule function via phosphine-mediated crosslinking and decaging chemistries. Thus, from a single cyclopropenone unit, one?in theory?can assemble, analyze, and activate biomolecules of interest. The versatility and accessibility of such reagents can provide a ?one-stop-shop? for tool users, bringing chemical probes more rapidly into the hands of non-specialists. Guided by strong preliminary data, our work will encompass the following specific aims: 1) Tune cyclopropenone reactivity for broad-spectrum biomolecule analyses; (2) Exploit ?latent? cyclopropenone reactivities for biomolecule assembly; and (3) Establish chemical triggers of biomolecule function. Under the first aim, we will examine the scope of the cyclopropenone-phosphine ligation, and identify scaffolds with suitable stability and reactivity profiles. In the second aim, we will capitalize on ?latent? cyclopropenone reactivities to assemble biomolecule conjugates. In the third aim, we will develop cyclopropenone triggers that can be used to crosslink and activate biomolecules of interest. Our approach is highly innovative, as it capitalizes on a unique reaction mechanism to access multi-functional bioorthogonal properties. The proposed research is significant, as it will provide versatile, easy-to-use chemical tools that are applicable to a broad spectrum of biomedical research. The probes will also enable experiments not possible with existing toolsets. Additionally, like other chemical technologies, the proposed reagents will likely inspire new discoveries in diverse fields.
The proposed research is relevant to public health because the development of new chemical tools is expected to facilitate studies of biomolecules in cells and other physiologically authentic environments. Such tools could guide the development of new classes of therapeutics and diagnostics. Thus, the proposed research is relevant to the NIH's mission that pertains to gaining fundamental knowledge about the nature of living systems and reducing the burdens of disease.