L-DNA Amidites and Supports

Mirror Image DNA (L-DNA):

• L-Nucleic acids, also known as Spiegelmers (“Spiegel” meaning mirror in German), are mirror-image oligonucleotide ligands composed of L-ribose or L-2′-deoxyribose sugar units.
• The chiral inversion in these nucleic acids results in high nuclease stability in plasma compared with natural D-nucleic acids, suggesting that Spiegelmers may display favorable in vivo behavior and present future potential for therapeutic and diagnostic applications.
•  As L-nucleic acids are perfect mirror-image form of the naturally occurring D-nucleic acids, L-nucleic acids have the same physical and chemical characteristics in terms of solubility, duplex stability and se­lectivity as D-DNA under non-chiral circumstances but form a left-helical double-helix.

ChemGenes has been instrumental in providing L-DNA amidites and supports of all four bases to researchers in this exciting field of mirror image nucleic acids. These amidites are supplied after thorough Quality Control including Optical Rotation validation.

Applications of Mirror Image Nucleic Acids:^1-7

L-Nucleic acids have been applied to the various interesting areas of nucleic acid therapeutics and diagnos­tics and few of them are described below.

• Aptamers¹ - Spiegelmers with excellent nuclease stability and its ability to fold into distinct three dimen­sional structures serves as promising candidates as aptamers.
• PCR² - It has been demonstrated that LT-PCR, a novel PCR technique, provides an efficient method for coding PCR products with a sequence-defined L-DNA tag.
• Microarray probes³ - Another significant application involves design of probes with a L-DNA sequence stem as part of probes having labels for recognition. This technique needs only one design and was ap­plied on a microarray platform (Figure 2). This is a very useful technique and has tremendous potential in wide applications using a single microarray platform.
• Agents for enantiomeric separation⁴ - A chiral stationary phase derived from an L-RNA aptamer is evalu­ated for the enantiomer separation of a series of herbicide molecules.
• Molecular Beacons⁵ - One significant research led to development of modified molecular beacons (MMB) consisting of L-DNA as the stem part of a Molecular Beacon (MB) probe, which prevent non specific fold­ing of the MB. These modified MBs, have been reported to provide excellent probes for many biological roles which MBs play (Figure 3).
• Nanotechnology⁶ - L-DNA can be readily self-assembled into designer discrete or periodic nanostruc­tures.
• L-RNA shows extraordinary stability in intracellular environments. Selective binding of long chain L-RNA to specific biological macromolecules has been searched via combinatorial libraries.⁷

Figure 1: Figure 2: Template Specific Primer Extension & Labelling Illustration of advantages of L-DNA (Zip Code) attached Primers for PCR and Microarray.³ (Reproduced by the kind permission of Oxford Press, UK).

Figure 2: Application of L-DNA attached molecular beacons (MB) avoiding non-specific binding (a-c). Design of Universal Microarray Platform.⁵ (Reproduced by the kind permission of Oxford Press, UK).

References:

1) Wlotzka, B et. al. Proc. Natl. Acad. Sci. U. S. A., 2002, 99, 8898-8902.

2) Hayashi, G et. al. ChemBioChem, 2007, 8, 169-171.

3) Hauser, N. C. et. al. Nucleic Acids Res., 2006, 34, 5101-5111.

4) Andre´, C. et. al. Electrophoresis, 2006, 27, 3254-3262.

5) Kim, Y. et. al. Nucleic Acids Res 2007, 35, 7279-7287.

6) Lin, C. et. al. Nano Lett. 2009, 9, 433-436.

7) Klussmann S, et. al. Nat. Biotech. 1996, 14, 1112-1115.