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| - | [[Image:2ahb.gif|left|200px]] | + | {{Seed}} |
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| | {{STRUCTURE_2ahb| PDB=2ahb | SCENE= }} | | {{STRUCTURE_2ahb| PDB=2ahb | SCENE= }} |
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| - | '''X-ray crystal structure of R46A,R161A mutant of Mycobacterium tuberculosis FabH'''
| + | ===X-ray crystal structure of R46A,R161A mutant of Mycobacterium tuberculosis FabH=== |
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| - | ==Overview==
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| - | Mycolic acids are the dominant feature of the Mycobacterium tuberculosis cell wall. These alpha-alkyl, beta-hydroxy fatty acids are formed by the condensation of two fatty acids, a long meromycolic acid and a shorter C(24)-C(26) fatty acid. The component fatty acids are produced via a combination of type I and II fatty acid synthases (FAS) with FAS-I products being elongated by FAS-II toward meromycolic acids. The beta-ketoacyl-acyl carrier protein (ACP) synthase III encoded by mtfabH (mtFabH) links FAS-I and FAS-II, catalyzing the condensation of FAS-I-derived acyl-CoAs with malonyl-acyl carrier protein (ACP). The acyl-CoA chain length specificity of mtFabH was assessed in vitro; the enzyme extended longer, physiologically relevant acyl-CoA primers when paired with AcpM, its natural partner, than with Escherichia coli ACP. The ability of the enzyme to use E. coli ACP suggests that a similar mode of binding is likely with both ACPs, yet it is clear that unique factors inherent to AcpM modulate the substrate specificity of mtFabH. Mutation of proposed key mtFabH residues was used to define their catalytic roles. Substitution of supposed acyl-CoA binding residues reduced transacylation, with double substitutions totally abrogating activity. Mutation of Arg(46) revealed its more critical role in malonyl-AcpM decarboxylation than in the acyl-CoA binding role. Interestingly, this effect was suppressed intragenically by Arg(161) --> Ala substitution. Our structural studies suggested that His(258), previously implicated in malonyl-ACP decarboxylation, also acts as an anchor point for a network of water molecules that we propose promotes deprotonation and transacylation of Cys(122).
| + | The line below this paragraph, {{ABSTRACT_PUBMED_16040614}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 16040614 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_16040614}} |
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| | ==About this Structure== | | ==About this Structure== |
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| | [[Category: Fabh]] | | [[Category: Fabh]] |
| | [[Category: Mtfabh]] | | [[Category: Mtfabh]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 19:02:59 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jul 28 10:50:06 2008'' |
Revision as of 07:50, 28 July 2008
Template:STRUCTURE 2ahb
X-ray crystal structure of R46A,R161A mutant of Mycobacterium tuberculosis FabH
Template:ABSTRACT PUBMED 16040614
About this Structure
2AHB is a Single protein structure of sequence from Mycobacterium tuberculosis. Full crystallographic information is available from OCA.
Reference
Probing the mechanism of the Mycobacterium tuberculosis beta-ketoacyl-acyl carrier protein synthase III mtFabH: factors influencing catalysis and substrate specificity., Brown AK, Sridharan S, Kremer L, Lindenberg S, Dover LG, Sacchettini JC, Besra GS, J Biol Chem. 2005 Sep 16;280(37):32539-47. Epub 2005 Jul 22. PMID:16040614
Page seeded by OCA on Mon Jul 28 10:50:06 2008
