The influence of a chiral amino acid on the helical handedness of PNA in solution and in crystals

TY - JOUR

T1 - The influence of a chiral amino acid on the helical handedness of PNA in solution and in crystals

AU - Rasmussen, Hanne B.

AU - Liljefors, T

AU - Petersson, B

AU - Nielsen, P E

AU - Liljefors, T

AU - Kastrup, Jette Sandholm Jensen

PY - 2004/2

Y1 - 2004/2

N2 - The X-ray structure of a self-complementary PNA hexamer (H-CGTACG-L-Lys-NH(2)) has been determined to 2.35 A resolution. The introduction of an L-lysine moiety has previously been shown to induce a preferred left-handedness of the PNA double helices in aqueous solution. However, in the crystal structure an equal amount of interchanging right- and left-handed helices is observed. The lysine moieties are pointing into large solvent channels and no significant interactions between this moiety and the remaining PNA molecule are observed. In contrast, molecular mechanics calculations show a preference for the left-handed helix of this hexameric PNA in aqueous solution as expected. The calculations indicate that the difference in the free energy of solvation between the left-handed and the right-handed helix is the determining factor for the preference of the left-handed helix in aqueous solution.

AB - The X-ray structure of a self-complementary PNA hexamer (H-CGTACG-L-Lys-NH(2)) has been determined to 2.35 A resolution. The introduction of an L-lysine moiety has previously been shown to induce a preferred left-handedness of the PNA double helices in aqueous solution. However, in the crystal structure an equal amount of interchanging right- and left-handed helices is observed. The lysine moieties are pointing into large solvent channels and no significant interactions between this moiety and the remaining PNA molecule are observed. In contrast, molecular mechanics calculations show a preference for the left-handed helix of this hexameric PNA in aqueous solution as expected. The calculations indicate that the difference in the free energy of solvation between the left-handed and the right-handed helix is the determining factor for the preference of the left-handed helix in aqueous solution.

KW - Amino Acids

KW - Computer Simulation

KW - Crystallography, X-Ray

KW - Lysine

KW - Models, Molecular

KW - Nucleic Acid Conformation

KW - Peptide Nucleic Acids

KW - Thermodynamics

U2 - 10.1080/07391102.2004.10506943

DO - 10.1080/07391102.2004.10506943

M3 - Journal article

C2 - 14692794

SN - 0739-1102

VL - 21

SP - 495

EP - 502

JO - Journal of Biomolecular Structure and Dynamics

JF - Journal of Biomolecular Structure and Dynamics

IS - 4

ER -