Genetic Engineering

B-DNA Motif for optical mask P = 3.4 nm r = 1.0 nm Symmetry : 10 1, C2 Base pairs : horizontal Molecular model B-DNA 0 P 3P/8 (cancels the 4th LL)

X-ray Diffraction by a Crystalline Fiber of a Li salt of B-DNA (Wilkins et al)

Optical simulations of X-ray diffraction by A-DNA See A. Lucas in J. Chem. Educ. 85, 737 (2008)

Optical simulations of X-ray diffraction by A-DNA See A. Lucas in J. Chem. Educ. 85, 737 (2008)

1953 Watson-Crick model Double helix Counter-oriented backbones Base pairing A-T, G-C via H-bonds Semi-conservative replication

A-DNA Motif P = 2.8 nm r = 0.9 nm Symmetry : 11 1, C2 Base pair angle :  40° A-DNA Molecular model C2 Two base pairs seen edge on 