Biomedical Engineering Reference
In-Depth Information
In DTS, two reactants are covalently linked to two complementary DNA strands,
each serving as either a template or a hybridization strand (reagent). Annealing of
the two oligonucleotides confines the reagents to the same region in space. The
local increase in reaction molarity allows the desired chemical reaction to occur,
even at nominal concentrations that are several orders of magnitude lower than
necessary for conventional solution-phase reaction. Interestingly, Gartner, Liu, and
co-workers demonstrated that within a distance of 30 nucleotides, the proximity
effect is nearly constant [74,75], thus enabling the use of various oligonucleotide
architectures, featuring multiple reagent-coding sequences at different positions on
the same DNA template [60,75,76].
Figure 11.13 shows three different DTS architectures developed for DNA-encoded
chemical library construction [70]. The end-of-helix setup (Figure 11.13a) is cur-
rently the most widely used approach, thanks to its versatility in incorporating differ-
ent chemical structures in multistep synthesis and its straightforward compatibility
with current procedures of library selection and decoding (e.g., high-throughput-
sequencing techniques) [60,70].
Using such architecture, the Harvard group described the first implementation of
DTS for the construction of DNA-encoded small-molecule libraries [60]. A proof-
of-concept library was synthesized using 48-mer 5
-lysine-modified oligonucleotide
FIGURE 11.13
DTS architectures. (a) End-of-helix architecture: reagents are displayed on
5
and 3
extremities of two complementary oligonucleotide sequences (DTS-reagent and tem-
plate). It is currently the most commonly used for DNA-encoded chemical library construction.
(b) Internal architecture: reagents displayed on the top of two oligonucleotides are confined in
a limited reaction space by means of a longer oligonucleotide template carrying both comple-
mentary sequences. (c) Similar to the internal embodiment, in hairpin configuration a longer
oligonucleotide serves as both reagent and template oligonucleotide.
