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| - | [[Image:1yhc.gif|left|200px]] | + | {{Seed}} |
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| | {{STRUCTURE_1yhc| PDB=1yhc | SCENE= }} | | {{STRUCTURE_1yhc| PDB=1yhc | SCENE= }} |
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| - | '''Crystal structure of Aquifex aeolicus LpxC deacetylase complexed with cacodylate'''
| + | ===Crystal structure of Aquifex aeolicus LpxC deacetylase complexed with cacodylate=== |
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| - | ==Overview==
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| - | UDP-3-O-((R)-3-hydroxymyristoyl)-N-acetylglucosamine deacetylase (LpxC) is a zinc-dependent enzyme that catalyzes the deacetylation of UDP-3-O-((R)-3-hydroxymyristoyl)-N-acetylglucosamine to form UDP-3-O-(R-hydroxymyristoyl)glucosamine and acetate. The structural similarity of the active site of LpxC to metalloproteases led to the proposal that LpxC functions via a metalloprotease-like mechanism. The pH dependence of k(cat)/Km catalyzed by Escherichia coli and Aquifex aeolicus LpxC displayed a bell-shaped curve (EcLpxC yields apparent pKa values of 6.4+/-0.1 and 9.1+/-0.1), demonstrating that at least two ionizations are important for maximal activity. Metal substitution and mutagenesis experiments suggest that the basic limb of the pH profile is because of deprotonation of a zinc-coordinated group such as the zinc-water molecule, whereas the acidic limb of the pH profile is caused by protonation of either Glu78 or His265. Furthermore, the magnitude of the activity decreases and synergy observed for the active site mutants suggest that Glu78 and His265 act as a general acid-base catalyst pair. Crystal structures of LpxC complexed with cacodylate or palmitate demonstrate that both Glu78 and His265 hydrogen-bond with the same oxygen atom of the tetrahedral intermediate and the product carboxylate. These structural features suggest that LpxC catalyzes deacetylation by using Glu78 and His265 as a general acid-base pair and the zinc-bound water as a nucleophile.
| + | The line below this paragraph, {{ABSTRACT_PUBMED_15705580}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 15705580 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_15705580}} |
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| | ==About this Structure== | | ==About this Structure== |
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| | [[Category: A aeolicus]] | | [[Category: A aeolicus]] |
| | [[Category: X-ray crystallography]] | | [[Category: X-ray crystallography]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 16:19:01 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jul 28 01:39:06 2008'' |
Revision as of 22:39, 27 July 2008
Template:STRUCTURE 1yhc
Crystal structure of Aquifex aeolicus LpxC deacetylase complexed with cacodylate
Template:ABSTRACT PUBMED 15705580
About this Structure
1YHC is a Single protein structure of sequence from Aquifex aeolicus. Full crystallographic information is available from OCA.
Reference
UDP-3-O-((R)-3-hydroxymyristoyl)-N-acetylglucosamine deacetylase functions through a general acid-base catalyst pair mechanism., Hernick M, Gennadios HA, Whittington DA, Rusche KM, Christianson DW, Fierke CA, J Biol Chem. 2005 Apr 29;280(17):16969-78. Epub 2005 Feb 10. PMID:15705580
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