1kar
From Proteopedia
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| 1kar, resolution 2.10Å () | |||||||||
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| Ligands: | , | ||||||||
| Non-Standard Residues: | |||||||||
| Gene: | HISD (Escherichia coli) | ||||||||
| Activity: | Histidinol dehydrogenase, with EC number 1.1.1.23 | ||||||||
| Related: | 1k75, 1kae, 1kah | ||||||||
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| Resources: | FirstGlance, OCA, RCSB, PDBsum | ||||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||||
L-HISTIDINOL DEHYDROGENASE (HISD) STRUCTURE COMPLEXED WITH HISTAMINE (INHIBITOR), ZINC AND NAD (COFACTOR)
Overview
The histidine biosynthetic pathway is an ancient one found in bacteria, archaebacteria, fungi, and plants that converts 5-phosphoribosyl 1-pyrophosphate to l-histidine in 10 enzymatic reactions. This pathway provided a paradigm for the operon, transcriptional regulation of gene expression, and feedback inhibition of a pathway. l-histidinol dehydrogenase (HisD, EC ) catalyzes the last two steps in the biosynthesis of l-histidine: sequential NAD-dependent oxidations of l-histidinol to l-histidinaldehyde and then to l-histidine. HisD functions as a homodimer and requires the presence of one Zn(2+) cation per monomer. We have determined the three-dimensional structure of Escherichia coli HisD in the apo state as well as complexes with substrate, Zn(2+), and NAD(+) (best resolution is 1.7 A). Each monomer is made of four domains, whereas the intertwined dimer possibly results from domain swapping. Two domains display a very similar incomplete Rossmann fold that suggests an ancient event of gene duplication. Residues from both monomers form the active site. Zn(2+) plays a crucial role in substrate binding but is not directly involved in catalysis. The active site residue His-327 participates in acid-base catalysis, whereas Glu-326 activates a water molecule. NAD(+) binds weakly to one of the Rossmann fold domains in a manner different from that previously observed for other proteins having a Rossmann fold.
About this Structure
1KAR is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
Mechanism of action and NAD+-binding mode revealed by the crystal structure of L-histidinol dehydrogenase., Barbosa JA, Sivaraman J, Li Y, Larocque R, Matte A, Schrag JD, Cygler M, Proc Natl Acad Sci U S A. 2002 Feb 19;99(4):1859-64. Epub 2002 Feb 12. PMID:11842181 Page seeded by OCA on Fri May 2 22:30:53 2008
