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'''L-HISTIDINOL DEHYDROGENASE (HISD) STRUCTURE COMPLEXED WITH L-HISTIDINE (PRODUCT), ZN AND NAD (COFACTOR)''' | '''L-HISTIDINOL DEHYDROGENASE (HISD) STRUCTURE COMPLEXED WITH L-HISTIDINE (PRODUCT), ZN AND NAD (COFACTOR)''' | ||
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[[Category: Sivaraman, J.]] | [[Category: Sivaraman, J.]] | ||
[[Category: 4 domain]] | [[Category: 4 domain]] | ||
[[Category: | [[Category: Hisd]] | ||
[[Category: | [[Category: Homodimer]] | ||
[[Category: | [[Category: L-histidine biosynthesis]] | ||
[[Category: | [[Category: L-histidinol dehydrogenase]] | ||
[[Category: | [[Category: Nad cofactor]] | ||
[[Category: | [[Category: Rossman fold]] | ||
[[Category: | [[Category: Zinc]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 22:30:12 2008'' | |||
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Revision as of 22:30, 2 May 2008
L-HISTIDINOL DEHYDROGENASE (HISD) STRUCTURE COMPLEXED WITH L-HISTIDINE (PRODUCT), ZN AND NAD (COFACTOR)
OverviewOverview
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 StructureAbout this Structure
1KAH is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
ReferenceReference
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 22:30:12 2008