Acta Crystallographica Section D

Biological Crystallography

Volume 57, Part 7 (July 2001)

research papers

Acta Cryst. (2001). D57, 981-989 [ doi:10.1107/S0907444901007120 ]

High-resolution neutron structure of nicotinamide adenine dinucleotide

B. Guillot, C. Lecomte, A. Cousson, C. Scherf and C. Jelsch

Abstract: The structure of the free-acid form of the coenzyme NAD⁺ was determined at 100 K from a single-crystal neutron experiment. NAD⁺ is the oxidized form of the coenzyme redox pair NAD⁺/NADH and plays an important role in the catalysis of biological processes. The molecule crystallizes in space group P1 with one NAD⁺ and four water molecules per unit cell. The structure is compared with the previous X-ray models of NAD⁺ [Reddy et al. (1981), J. Am. Chem. Soc. 103, 907-914; Parthasarathy & Fridey (1984b), Science, 226, 969-971; Guillot et al. (2000), Acta Cryst. C56, 726-728]. The crystal packing and the hydrogen-bond pattern are discussed as well as four short C-H $\cdots$ O contacts involving the pyridine and adenine rings. The structure displays stereochemical distortions owing to the hydrogen bonding and crystal-packing constraints, reflecting the adaptability of the NAD⁺ molecule in various chemical environments.

NDB reference: ur0013

Keywords: neutron diffraction; nicotinamide adenine dinucleotide; NAD⁺.