A four-base paired genetic helix with expanded size.
We describe a new molecular class of genetic-pairing system that has a native DNA backbone but has all four base pairs replaced by new, larger pairs. The base pairs include size-expanded analogs of thymine and of adenine, both extended by the width of a benzene ring (2.4 A). The expanded-diameter double helices are more thermodynamically stable than the Watson-Crick helix, likely because of enhanced base stacking. Structural data confirm a right-handed, double-stranded, and base-paired helical form. Because of the larger base size, all the pairs of this helical system are fluorescent, which suggests practical applications in detection of natural DNA and RNA. Our findings establish that there is no apparent structural or thermodynamic prohibition against genetic systems having sizes different from the natural one.
Liu
Haibo
H
Department of Chemistry, Stanford University, Stanford, CA 94305-5080, USA.
Gao
Jianmin
J
Lynch
Stephen R
SR
Saito
Y David
YD
Maynard
Lystranne
L
Kool
Eric T
ET
D000225:Adenine / Q000031:analogs & derivatives* / Q000737:chemistry; D020029:Base Pairing; D001483:Base Sequence; D001554:Benzene / Q000737:chemistry; D002942:Circular Dichroism; D006860:Hydrogen Bonding; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D009690:Nucleic Acid Conformation; D009691:Nucleic Acid Denaturation; D009693:Nucleic Acid Hybridization; D009838:Oligodeoxyribonucleotides / Q000737:chemistry*; D013696:Temperature; D013816:Thermodynamics; D013941:Thymine / Q000031:analogs & derivatives* / Q000737:chemistry
D009838:Oligodeoxyribonucleotides; D001554:Benzene; D000225:Adenine; D013941:Thymine