Chaput, "A parallel stranded G-quadruplex composed of threose nucleic acid (TNA)," Biopolymers, vol.
Caption: FIGURE 5: Structures of 5-(benzofuran-2-yl)uracil (1); threose dinucleotide (2); R- (3) and S-isomer (4) of acyclic-uracil derivatives and the n-propyl spacer (5).
Instead of those sugars, each XNA has a different molecule in its backbone: A five-carbon sugar called arabinose in ANA, the ringed structure anhydrohexitol in HNA, and threose, a four-carbon sugar in TNA.
Earlier work showed that TNA can pair up with DNA and RNA, and TNA's four-carbon sugar threose is a simpler molecule than the five-carbon sugars found in DNA and RNA.
Working with colleagues at the University of Nottingham, they have made the first step towards showing how simple sugars -- threose
and erythrose -- developed.
, a metabolite of ascorbic acid, increases the AGE content of articular cartilage in vitro (34).
One called TNA replaces RNA's ribose sugar with a sugar called threose
. Another variant is called morpholino NA.