Ordered multistep synthesis in a single solution directed by DNA templates.
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Alkenes↗
Biomedical subjects
Thomas M Snyder
Publications and source records attributed to Thomas M Snyder.
DNA-templated functional group transformations enable sequence-programmed synthesis using small-molecule reagents.
DNA-templated organic synthesis (DTS) has previously been used primarily to direct coupling reactions between two DNA-linked reactants. In some cases, reactants are difficult or impossible to tether to DNA oligonucleotides. The development of strategies that enable non-DNA linked small-molecule reagents to participate in sequence-programmed synthesis therefore would significantly expand the capabilities of DTS. We developed efficient DNA-templated functional group transformations of template-linked azides into corresponding amines, carboxylic acids, and thiols. The application of these reactions to a single-solution mixture of four template-linked organic azides enabled each azide to be transformed sequence specifically into a sulfonamide, carbamate, urea, or thiourea using small-molecule sulfonyl chloride, chloroformate, isocyanate, or isothiocyanate reagents not tethered to DNA. Only the four desired products were observed, without formation of any of the 12 possible undesired cross-products. Our results represent a new approach to small molecule diversification in a DNA-programmed manner.
Amines↗
Reaction discovery enabled by DNA-templated synthesis and in vitro selection.
Current approaches to reaction discovery focus on one particular transformation. Typically, researchers choose substrates based on their predicted ability to serve as precursors for the target structure, then evaluate reaction conditions for their ability to effect product formation. This approach is ideal for addressing specific reactivity problems, but its focused nature might leave many areas of chemical reactivity unexplored. Here we report a reaction discovery approach that uses DNA-templated organic synthesis and in vitro selection to simultaneously evaluate many combinations of different substrates for bond-forming reactions in a single solution. Watson-Crick base pairing controls the effective molarities of substrates tethered to DNA strands; bond-forming substrate combinations are then revealed using in vitro selection for bond formation, PCR amplification and DNA microarray analysis. Using this approach, we discovered an efficient and mild carbon-carbon bond-forming reaction that generates an enone from an alkyne and alkene using an inorganic palladium catalyst. Although this approach is restricted to conditions and catalysts that are at least partially compatible with DNA, we expect that its versatility and efficiency will enable the discovery of additional reactions between a wide range of substrates.
Alkenes↗
Reversible association of telechelic molecules: an application of graph theory.
We develop a method for calculating the exact free energy of tree clusters formed from associating telechelic molecules. The method uses the concept of rooted trees from the graph theory to enumerate all topologically distinct trees having a maximum degree of branching; it recursively separates the trees into different classes based on their connectivity, thus enabling the exact summation of the trees weighted by their respective Boltzmann factors. We apply our method to studying the pregel properties in pure telechelic solutions and in mixed telechelic and single-associating-end polymer solutions. We highlight the effect of energetic tendency for branching in the former and the effect of competitive association in the latter.
Journal Article↗
DNA-templated organic synthesis and selection of a library of macrocycles.
The translation of nucleic acid libraries into corresponding synthetic compounds would enable selection and amplification principles to be applied to man-made molecules. We used multistep DNA-templated organic synthesis to translate libraries of DNA sequences, each containing three "codons," into libraries of sequence-programmed synthetic small-molecule macrocycles. The resulting DNA-macrocycle conjugates were subjected to in vitro selections for protein affinity. The identity of a single macrocycle possessing known target protein affinity was inferred through the sequence of the amplified DNA template surviving the selection. This work represents the translation, selection, and amplification of libraries of nucleic acids encoding synthetic small molecules rather than biological macromolecules.
Amides↗
Highly sensitive in vitro selections for DNA-linked synthetic small molecules with protein binding affinity and specificity.
We have developed in vitro selections for DNA-linked synthetic small molecules with protein binding affinity and specificity. These selections require only generally accessible equipment, offer high degrees of enrichment of active molecules from mixtures of predominantly inactive species, can be applied to a variety of unrelated proteins, and require approximately 108-fold less material than existing synthetic molecule screening methods. Iterating these selections multiplies the net enrichment of active molecules, enabling enormous overall enrichment factors exceeding 106 to be achieved. Further, the selections can be adapted to select for binding specificity in addition to binding affinity. The application of methods described in this work may play a key role in the discovery of desired molecules from DNA-templated synthetic libraries.
Combinatorial Chemistry Techniques↗