Capture-Tag-Release: A Strategy for Small Molecule Labeling of Native Enzymes

Bioorthogonal Reactions of Triarylphosphines and Related Analogues

Bioorthogonal phosphines were introduced in the context of the Staudinger ligation over 20 years ago. Since that time, phosphine probes have been used in myriad applications to tag azide-functionalized biomolecules. The Staudinger ligation also paved the way for the development of other phosphorus-based chemistries, many of which are widely employed in biological experiments. Several reviews have highlighted early achievements in the design and application of bioorthogonal phosphines. This review summarizes more recent advances in the field. We discuss innovations in classic Staudinger-like transformations that have enabled new biological pursuits. We also highlight relative newcomers to the bioorthogonal stage, including the cyclopropenone-phosphine ligation and the phospha-Michael reaction. The review concludes with chemoselective reactions involving phosphite and phosphonite ligations. For each transformation, we describe the overall mechanism and scope. We also showcase efforts to fine-tune the reagents for specific functions. We further describe recent applications of the chemistries in biological settings. Collectively, these examples underscore the versatility and breadth of bioorthogonal phosphine reagents.

Triazole formation of phosphinyl alkynes with azides through transient protection of phosphine by copper

An efficient preparation method of functionalized phosphines by copper-catalyzed azide-alkyne cycloaddition (CuAAC) through the transient protection of phosphine from the Staudinger reaction is disclosed. Diverse phosphines were prepared from phosphinyl alkynes and azides by the click reaction at the ethynyl group without damaging the phosphinyl group. Double- and triple-click assemblies of azides were accomplished by triazole formations and robust azaylide formation.

Activity-Based Phosphatidylinositol Kinase Probes Detect Changes to Protein-Protein Interactions During Hepatitis C Virus Replication

Protein-protein interactions are integral to host-virus interactions and can contribute significantly to enzyme regulation by changing the localization of both host and viral enzymes within the cell, inducing conformational change relevant to enzyme activity or recruiting other additional proteins to form functional complexes. Identifying the interactors of active enzymes using an activity-based protein profiling probe has allowed us to characterize both normal enzyme activation mechanisms and the manner by which these mechanisms are hijacked and altered by the hepatitis C virus (HCV). Here, we report use of a novel activity-based probe, PIKBPyne, which labels phosphatidylinositol kinases (PIKs) in an activity-based manner, to investigate HCV-dependent changes in protein-protein interactions for PI4KB. Herein, we report the synthesis of new variations on PIKBPyne, compare their ability to label the interacting partners of PI4KB, and demonstrate the utility of our approach in characterizing virus-mediated changes to host function.

Innovations in Undergraduate Chemical Biology Education

Chemical biology derives intellectual vitality from its scientific interface: applying chemical strategies and perspectives to biological questions. There is a growing need for chemical biologists to synergistically integrate their research programs with their educational activities to become holistic teacher-scholars. This review examines how course-based undergraduate research experiences (CUREs) are an innovative method to achieve this integration. Because CUREs are course-based, the review first offers strategies for creating a student-centered learning environment, which can improve students' outcomes. Exemplars of CUREs in chemical biology are then presented and organized to illustrate the five defining characteristics of CUREs: significance, scientific practices, discovery, collaboration, and iteration. Finally, strategies to overcome common barriers in CUREs are considered as well as future innovations in chemical biology education.