1KQP
NH3-DEPENDENT NAD+ SYNTHETASE FROM BACILLUS SUBTILIS AT 1 A RESOLUTION
Summary for 1KQP
Entry DOI | 10.2210/pdb1kqp/pdb |
Related | 1EE1 1FYD 1IFX 1IH8 1NSY 2NSY |
Descriptor | NH(3)-dependent NAD(+) synthetase, MAGNESIUM ION, 1,2-ETHANEDIOL, ... (6 entities in total) |
Functional Keywords | ligase, amidotransferase, atp pyrophosphatase, nad-adenylate |
Biological source | Bacillus subtilis |
Total number of polymer chains | 2 |
Total formula weight | 63701.44 |
Authors | Symersky, J.,Devedjiev, Y.,Moore, K.,Brouillette, C.,DeLucas, L. (deposition date: 2002-01-07, release date: 2002-06-28, Last modification date: 2023-08-16) |
Primary citation | Symersky, J.,Devedjiev, Y.,Moore, K.,Brouillette, C.,DeLucas, L. NH3-dependent NAD+ synthetase from Bacillus subtilis at 1 A resolution. Acta Crystallogr.,Sect.D, 58:1138-1146, 2002 Cited by PubMed Abstract: The final step of NAD+ biosynthesis includes an amide transfer to nicotinic acid adenine dinucleotide (NaAD) catalyzed by NAD+ synthetase. This enzyme was co-crystallized in microgravity with natural substrates NaAD and ATP at pH 8.5. The crystal was exposed to ammonium ions, synchrotron diffraction data were collected and the atomic model was refined anisotropically at 1 A resolution to R = 11.63%. Both binding sites are occupied by the NAD-adenylate intermediate, pyrophosphate and two magnesium ions. The atomic resolution of the structure allows better definition of non-planar peptide groups, reveals a low mean anisotropy of protein and substrate atoms and indicates the H-atom positions of the phosphoester group of the reaction intermediate. The phosphoester group is protonated at the carbonyl O atom O7N, suggesting a carbenium-ion structure stabilized by interactions with two solvent sites presumably occupied by ammonia and a water molecule. A mechanism is proposed for the second catalytic step, which includes a nucleophilic attack by the ammonia molecule on the intermediate. PubMed: 12077433DOI: 10.1107/S0907444902006698 PDB entries with the same primary citation |
Experimental method | X-RAY DIFFRACTION (1.03 Å) |
Structure validation
Download full validation report
