Peptide Logic Circuits Based on Chemoenzymatic Ligation for Programmable Cell Apoptosis

Synthetic Peptides with Genetic-Codon-Tailored Affinity for Assembling Tetraspanin CD81 at Cell Interfaces and Inhibiting Cancer Metastasis

Probing biomolecular interactions at cellular interfaces is crucial for understanding and interfering with life processes. Although affinity binders with site specificity for membrane proteins are unparalleled molecular tools, a high demand remains for novel multi-functional ligands. In this study, a synthetic peptide (APQQ) with tight and specific binding to the untargeted extracellular loop of CD81 evolved from a genetically encoded peptide pool. With tailored affinity, APQQ flexibly accesses, site-specifically binds, and forms a complex with CD81, enabling in-situ tracking of the dynamics and activity of this protein in living cells, which has rarely been explored because of the lack of ligands. Furthermore, APQQ triggers the relocalization of CD81 from diffuse to densely clustered at cell junctions and modulates the interplay of membrane proteins at cellular interfaces. Motivated by these, efficient suppression of cancer cell migration, and inhibition of breast cancer metastasis were achieved in vivo.

Engineering Cell-Surface Receptors with DNA Nanotechnology for Cell Manipulation

Cell-surface receptors play pivotal roles in the regulation of cell fate. Molecular engineering of cell-surface receptors enables control of cell signaling and manipulation of cell behavior in a user-defined way. Currently, the development of chemical-biological approaches for non-genetic engineering and regulation of membrane receptors is attracting significant interest. Recent research advances in functional nucleic acids and DNA nanotechnology have made it possible to use DNA as a new and promising molecular toolkit for controlling receptor-mediated signaling and cell fates. In this minireview we summarize the advances in the use of DNA nanotechnology for the spatiotemporal regulation of cell receptors and highlight practical applications in manipulating cell functions including cell adhesion, cell-cell contact, cell migration, and cellular immunity. We also provide a perspective on the potential of and challenges facing DNA-based receptor engineering in future applications of cell manipulation and cell-based therapy.

Biocomputing for Portable, Resettable, and Quantitative Point-of-Care Diagnostics: Making the Glucose Meter a Logic-Gate Responsive Device for Measuring Many Clinically Relevant Targets

It is recognized that biocomputing can provide intelligent solutions to complex biosensing projects. However, it remains challenging to transform biomolecular logic gates into convenient, portable, resettable and quantitative sensing systems for point-of-care (POC) diagnostics in a low-resource setting. To overcome these limitations, the first design of biocomputing on personal glucose meters (PGMs) is reported, which utilizes glucose and the reduced form of nicotinamide adenine dinucleotide as signal outputs, DNAzymes and protein enzymes as building blocks, and demonstrates a general platform for installing logic-gate responses (YES, NOT, INHIBIT, NOR, NAND, and OR) to a variety of biological species, such as cations (Na+ ), anions (citrate), organic metabolites (adenosine diphosphate and adenosine triphosphate) and enzymes (pyruvate kinase, alkaline phosphatase, and alcohol dehydrogenases). A concatenated logical gate platform that is resettable is also demonstrated. The system is highly modular and can be generally applied to POC diagnostics of many diseases, such as hyponatremia, hypernatremia, and hemolytic anemia. In addition to broadening the clinical applications of the PGM, the method reported opens a new avenue in biomolecular logic gates for the development of intelligent POC devices for on-site applications.

Transpeptidation-directed intramolecular bipartite tetracysteine display for sortase activity assay

We developed a simple, label-free and homogenous assay to quantitively evaluate SrtA-catalyzed transpeptidation reaction.