1kaq
From Proteopedia
Structure of Bacillus subtilis Nicotinic Acid Mononucleotide Adenylyl Transferase
Overview
The nadD gene, encoding the enzyme nicotinic acid mononucleotide (NaMN) adenylyltransferase (AT), is essential for the synthesis of NAD and subsequent viability of the cell. The nadD gene in Bacillus subtilis (yqeJ) was identified by sequence homology with other bacterial nadD genes and by biochemical characterization of the gene product. NaMN AT catalyzes the reversible adenylation of both NaMN and the nicotinamide mononucleotide (NMN) but shows specificity for the nicotinate. In contrast to other known NMN ATs, biophysical characterizations reveal it to be a dimer. The NaMN AT crystal structure was determined for both the apo enzyme and product-bound form, to 2.1 and 3.2 A, respectively. The structures reveal a "functional" dimer conserved in both crystal forms and a monomer fold common to members of the nucleotidyl-transferase alpha/beta phosphodiesterase superfamily. A structural comparison with family members suggests a new conserved motif (SXXXX(R/K)) at the N terminus of an alpha-helix, which is not part of the shared fold. Interactions of the nicotinic acid with backbone atoms indicate the structural basis for specificity.
About this Structure
1KAQ is a Single protein structure of sequence from Bacillus subtilis. Full crystallographic information is available from OCA.
Reference
Identification, characterization, and crystal structure of Bacillus subtilis nicotinic acid mononucleotide adenylyltransferase., Olland AM, Underwood KW, Czerwinski RM, Lo MC, Aulabaugh A, Bard J, Stahl ML, Somers WS, Sullivan FX, Chopra R, J Biol Chem. 2002 Feb 1;277(5):3698-707. Epub 2001 Nov 9. PMID:11704676 Page seeded by OCA on Fri May 2 22:30:47 2008
