Evolutionary Molecular Engineering
In the theory of evolution by natural selection, the number of species that lack enough fitness, and are not compatible with the environment, is gradually declined (natural selection).
SELEX (Systematic Evolution of Ligands by EXponential Enrichment), also referred to in vitro evolution, is combinatorial chemistry for producing large single-stranded DNA or RNA libraries that specifically bind to a target ligand. These single-stranded DNA or RNA are commonly referred to as aptamers.
The process begins with the synthesis of a very large nucleic acid library consisting of randomly generated sequences. The sequences in the library are exposed to the target ligand – which may be a protein or a small organic compound – and those that do not bind the target are removed. The bound sequences are eluted and amplified by PCR to prepare for subsequent rounds of selection in which the stringency of the elution conditions can be increased to identify the high affinity-binding sequences. molecules could have significant clinical effects.
MACE® (Microbead-Assisted Capillary Electrophoresis) Technology
MACE® Technology is a novel and efficient Capillary Electrophoresis (CE) partitioning method to separate high-affinity target-bound aptamers from a very large nucleic acid library pool.
With MACE® Technology, the specific aptamers and target-immobilized magnetic microbeads complexes can be efficiently separated in the CE even from the first selection round by UV detection using the absorbance change from the light scattering of the microbead complexes.
MACE® Technology efficiency has been verified in several projects and many high affinity and specificity aptamers candidates have been successfully identified for several protein and small molecule targets (for more information, please click here).
MACE® Technology has been developed by Dr. Yoshimoto at The University of Tokyo, and granted patent in USA, Taiwan, and China.
Evolutionary Molecular Engineering methods in Drug Discovery
Beside SELEX, there are several evolutionary molecular engineering methods that used for the isolation of high affinity hits from large libraries pool including phage-display, liposome-display, mRNA-display, cDNA-display, DNA-encoded libraries, and VHH antibody libraries. Our MACE® Technology technology has the potential to be used in combination with all the above evolutionary molecular engineering selection methods to improve their quality and separation efficiency.
MACE® for Protein Target
MACE® for Small Molecules Target
We succeeded to obtain a highly specific DNA aptamer against methotrexate, a low-molecular-weight anticancer drug (0.45 kDa), with just three rounds of selection. Our MACE-SELEX technology has been demonstrated to be efficiently applicable not only to protein targets but also to small molecules. Furthermore, by bispecific identified MTX-binding DNA aptamer, we succeeded to construct a new analytical method with high detection sensitivity.
In the future, we can expect to promote the use of bispecific aptamers not only in the field of diagnostic but also in therapeutic.