Rational truncation of aptamer for cross-species application to detect krait envenomation

Abstract

In majority of snakebite cases, the snake responsible for the bite remains unidentified. The traditional snakebite diagnostics method relies upon clinical symptoms and blood coagulation assays that do not provide accurate diagnosis which is important for epidemiological as well as diagnostics point of view. On the other hand, high batch-to-batch variations in antibody performance limit its application for diagnostic assays. In recent years, nucleic acid aptamers have emerged as a strong chemical rival of antibodies due to several obvious advantages, including but not limited to in vitro generation, synthetic nature, ease of functionalization, high stability and adaptability to various diagnostic formats. In the current study, we have rationally truncated an aptamer developed for α-Toxin of Bungarus multicinctus and demonstrated its utility for the detection of venom of Bungarus caeruleus. The truncated aptamer α-Tox-T2 (26mer) is found to have greater affinity than its 40-mer parent counterpart α-Tox-FL. The truncated aptamers are characterized and compared with parent aptamer for their binding, selectivity, affinity, alteration in secondary structure and limit of detection. Altogether, our findings establish the cross-species application of a DNA aptamer generated for α-Toxin of Bungarus multicinctus (a snake found in Taiwan and China) for the reliable detection of venom of Bungarus caeruleus (a snake found in the Indian subcontinent).

Cytotoxin antibody-based colourimetric sensor for field-level differential detection of elapid among big four snake venom

“…A significantly lower immunoreactivity and binding affinity towards krait venom as compared to cobra venom may be attributed to the lower level of expression of cytotoxins in krait venom ( Fig 2B ). Aptamers have been selected against Phospholipase A2 for the detection of krait venom [ 42 , 43 ]. Even so, the universal presence of this protein in both elapid and viper venoms raise questions on its utility as a marker for species-specific venom identification.…”

Paper-based aptamer-antibody biosensor for gluten detection in a deep eutectic solvent (DES)

“…In this approach, the truncated aptamer Gli4-T was employed as capture element while the 401/21 antibody was employed as the signaling element. In a previous work, the process of truncation of non-essential nucleotides was reported to improve the accessibility of the target to the aptamer, allowing the formation of a stronger aptamer-target complex [44]. Gli4-T is the truncated aptamer derived from Gli4 which preserves a motif capable of effectively binding gliadin (Fig.…”

Antibodies, Nanobodies, or Aptamers—Which Is Best for Deciphering the Proteomes of Non-Model Species?

“…However, where there is divergence and homology is decreased, the binding site may only be amenable to very small binders that have been generated to other species' proteins. In a similar manner to nanobodies being smaller versions of antibodies, an aptamer is fairly easy to truncate to its smallest functional form, which may increase its possibility of binding to multiple species [70][71][72] Of note for the use of combinatorial libraries, it is possible to take the sequence of the targeting moiety and mutate this sequence with multiple mutations to find one that will bind to a different species' protein, though depending on the format of the assay and the knowledge of the other protein, this may not be possible [73]. However, there are several other protocols available that might be amenable for developing targeting agents.…”

“…Interestingly, and highlighting the point earlier made about the size of the binding region, there have been a few studies that have truncated aptamers to enhance their cross-species reactivity. For example, Dhiman et al truncated an aptamer from 40 nucleotides to 26 nucleotides to recognize toxins from two different snake species [70]. One study has investigated the ability of three different aptamers to bind to thrombin in six different species (human, bovine, porcine, rabbit, rat, and mouse).…”