Natural DNA is exquisitely evolved to store genetic information. The chirally inverted l -DNA, possessing the same informational capacity but resistant to biodegradation, may serve as a robust, bioorthogonal information repository. Here we chemically synthesize a 90-kDa high-fidelity mirror-image Pfu DNA polymerase that enables accurate assembly of a kilobase-sized mirror-image gene. We use the polymerase to encode in l -DNA an 1860 paragraph by Louis Pasteur that first proposed a mirror-image world of biology. We realize chiral steganography by embedding a chimeric d -DNA/ l -DNA key molecule in a d -DNA storage library, which conveys a false or secret message depending on the chirality of reading. Furthermore, we show that a trace amount of an l -DNA barcode preserved in water from a local pond remains amplifiable and sequenceable for 1 year, whereas a d -DNA barcode under the same conditions could not be amplified after 1 day. These next-generation mirror-image molecular tools may transform the development of advanced mirror-image biology systems and pave the way for the realization of the mirror-image central dogma and exploration of their applications.
Mirror-image aptamers made from chirally inverted nucleic acids are nuclease-resistant and exceptionally biostable, opening up opportunities for unique applications. However, the directed evolution and selection of mirror-image aptamers directly from large randomized l -DNA libraries has, to our knowledge, not been demonstrated previously. Here, we developed a ‘mirror-image selection’ scheme for the directed evolution and selection of biostable l -DNA aptamers with a mirror-image DNA polymerase. We performed iterative rounds of enrichment and mirror-image polymerase chain reaction (PCR) amplification of l -DNA sequences that bind native human thrombin, in conjunction with denaturing gradient gel electrophoresis (DGGE) to isolate individual aptamers and l -DNA sequencing-by-synthesis to determine their sequences. Based on the selected l -DNA aptamers, we designed biostable thrombin sensors and inhibitors, which remained functional in physiologically relevant nuclease-rich environments, even in the presence of human serum that rapidly degraded d -DNA aptamers. Mirror-image selection of biostable l -DNA aptamers directly from large randomized l -DNA libraries greatly expands the range of biomolecules that can be targeted, broadening their applications as biostable sensors, therapeutics and basic research tools.
危险品化学品经营许可证（带存储）