13th August 2019
Under pathophysiological conditions, transcription of proteins can lead to changes in amino acid structure known as that can either destroy their activity or impart them with new functionality. These transformations can be indicators of disease occurrence or progression and therefore point mutations on proteins can serve as useful biomarkers for disease. However, their discovery and detection in biological fluids that are complex mixture of proteins becomes more challenging. Aptamers have shown to address this challenge by discriminating against proteins with mutations due to their ease of synthesis in vitro, along with their chemical stability and high specificity and affinity towards the target.
Because of our robust process, we have successfully selected aptamers that have shown to discriminate closely related proteins even with minor changes. One such example includes successful generation of modified RNA aptamers against the mutated forms of RNA binding protein involved in mRNA processing including coupling transcription and splicing processes in their normal state. Our aptamers could specifically differentiate between the wild type (counter-target protein) and mutant (target) forms of the protein. In this case, individual aptamers were isolated and characterized using BLI which showed high specificity and affinity for the mutated forms of the protein (Figure 1).
Figure 1. An example of our data showing individual aptamer clones A, B and C targeting mutant protein (green curve, target) in the low nanomolar affinity range. Negligible binding of aptamer clones was seen with the wild type protein (red curve, counter target). The naïve population (unselected library) showed negligible binding to the protein target (blue and yellow curve).
Having high levels of selectivity is critical to bring next generation bio-makers into the clinic. Our aptamers can be tailored for a certain molecule domain and therefore can become the golden receptor to specifically detect aberrant changes on each protein, providing new diagnostic tools for early detection of cancer. Here we have provided proof-of-principle that with careful introduction of the closely related counter-selection targets during the selection process, a population of aptamers with exquisite discrimination can be isolated. Moreover, our sensitive and robust analytical tests are able to detect small changes in the conformation of therapeutic protein.
If you would like to learn more about the protein selection strategy using our high throughput process, please contact us using the form below.