Open AccessComparison between the orthorhombic and tetragonal forms of the heptamer sequence d[GCG(xT)GCG]/d(CGCACGC)
Author(s) -
Robeyns Koen,
Herdewijn Piet,
Van Meervelt Luc
Publication year - 2010
Publication title -
acta crystallographica section f
Language(s) - English
Resource type - Journals
ISSN - 1744-3091
DOI - 10.1107/s1744309110031696
Subject(s) - orthorhombic crystal system , tetragonal crystal system , crystallography , chemistry , resolution (logic) , crystal structure , ring (chemistry) , sequence (biology) , nucleic acid , stereochemistry , organic chemistry , biochemistry , artificial intelligence , computer science
Cyclohexene nucleic acid (CeNA) building blocks can be introduced into natural DNA sequences without a large conformational influence because of the ability of the six‐membered sugar ring to mimic both the C2′‐ endo and C3′‐ endo conformations of the naturally occurring ribofuranose sugar ring. The non‐self‐complementary DNA sequence d[GCG(xT)GCG]/d(CGCACGC) with one incorporated CeNA (xT) moiety crystallizes in two forms: orthorhombic and tetragonal. The tetragonal form, which diffracts to 3 Å resolution, is a kinetically stable polymorph of the orthorhombic form [Robeyns et al. (2010), Artificial DNA , 1 , 1–7], which diffracts to 1.17 Å resolution and is the thermodynamically stable form of the CeNA‐incorporated duplex. Here, the two structures are compared, with special emphasis on the differences in crystal packing and the irreversible conversion of the kinetic form into the high‐resolution diffracting thermodynamic form.