1k75 | pdb_00001k75
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| 1k75, resolution 1.75Å | |||||||||||||
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| Ligands: | SO4 and GOL | ||||||||||||
| Gene: | hisD (Escherichia coli) | ||||||||||||
| Activity: | Histidinol dehydrogenase, with EC number 1.1.1.23 | ||||||||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||||||||
The L-histidinol dehydrogenase (hisD) structure implicates domain swapping and gene duplication.
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
1K75 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 Thu Mar 20 12:13:28 2008
Proteopedia Page Contributors and Editors (what is this?)
- Pages with broken file links
- Escherichia coli
- Histidinol dehydrogenase
- Single protein
- BSGI, Montreal-Kingston Bacterial Structural Genomics Initiative.
- Barbosa, J A.R G.
- Cygler, M.
- Larocque, R.
- Li, Y.
- Matte, A.
- Schrag, J.
- Sivaraman, J.
- GOL
- SO4
- 4 domain
- Bsgi
- Hisd
- Homodimer
- L-histidine biosynthesis
- L-histidinol dehydrogenase
- Montreal-kingston bacterial structural genomics initiative
- Nad cofactor
- Rossman fold
- Structural genomic
- Zinc
