2v23
From Proteopedia
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caption="2v23, resolution 1.80Å" /> | caption="2v23, resolution 1.80Å" /> | ||
'''STRUCTURE OF CYTOCHROME C PEROXIDASE MUTANT N184R Y36A'''<br /> | '''STRUCTURE OF CYTOCHROME C PEROXIDASE MUTANT N184R Y36A'''<br /> | ||
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| + | ==Overview== | ||
| + | Isoniazid (INH, isonicotinic acid hydrazine) is one of only two therapeutic agents effective in treating tuberculosis. This prodrug is activated by the heme enzyme catalase peroxidase (KatG) endogenous to Mycobacterium tuberculosis but the mechanism of activation is poorly understood, in part because the binding interaction has not been properly established. The class I peroxidases ascorbate peroxidase (APX) and cytochrome c peroxidase (CcP) have active site structures very similar to KatG and are also capable of activating isoniazid. We report here the first crystal structures of complexes of isoniazid bound to APX and CcP. These are the first structures of isoniazid bound to any activating enzymes. The structures show that isoniazid binds close to the delta-heme edge in both APX and CcP, although the precise binding orientation varies slightly in the two cases. A second binding site for INH is found in APX at the gamma-heme edge close to the established ascorbate binding site, indicating that the gamma-heme edge can also support the binding of aromatic substrates. We also show that in an active site mutant of soybean APX (W41A) INH can bind directly to the heme iron to become an inhibitor and in a different mode when the distal histidine is replaced by alanine (H42A). These structures provide the first unambiguous evidence for the location of the isoniazid binding site in the class I peroxidases and provide rationalization of isoniazid resistance in naturally occurring KatG mutant strains of M. tuberculosis. | ||
==About this Structure== | ==About this Structure== | ||
2V23 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Saccharomyces_cerevisiae Saccharomyces cerevisiae] with <scene name='pdbligand=HEM:'>HEM</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Cytochrome-c_peroxidase Cytochrome-c peroxidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.11.1.5 1.11.1.5] Known structural/functional Site: <scene name='pdbsite=AC1:Hem+Binding+Site+For+Chain+A'>AC1</scene>. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2V23 OCA]. | 2V23 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Saccharomyces_cerevisiae Saccharomyces cerevisiae] with <scene name='pdbligand=HEM:'>HEM</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Cytochrome-c_peroxidase Cytochrome-c peroxidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.11.1.5 1.11.1.5] Known structural/functional Site: <scene name='pdbsite=AC1:Hem+Binding+Site+For+Chain+A'>AC1</scene>. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2V23 OCA]. | ||
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| + | ==Reference== | ||
| + | The Tuberculosis Prodrug Isoniazid Bound to Activating Peroxidases., Metcalfe C, Macdonald IK, Murphy EJ, Brown KA, Raven EL, Moody PC, J Biol Chem. 2008 Mar 7;283(10):6193-6200. Epub 2007 Dec 5. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=18056997 18056997] | ||
[[Category: Cytochrome-c peroxidase]] | [[Category: Cytochrome-c peroxidase]] | ||
[[Category: Saccharomyces cerevisiae]] | [[Category: Saccharomyces cerevisiae]] | ||
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[[Category: transit peptide]] | [[Category: transit peptide]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri Mar 14 09:43:31 2008'' |
Revision as of 07:43, 14 March 2008
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STRUCTURE OF CYTOCHROME C PEROXIDASE MUTANT N184R Y36A
Overview
Isoniazid (INH, isonicotinic acid hydrazine) is one of only two therapeutic agents effective in treating tuberculosis. This prodrug is activated by the heme enzyme catalase peroxidase (KatG) endogenous to Mycobacterium tuberculosis but the mechanism of activation is poorly understood, in part because the binding interaction has not been properly established. The class I peroxidases ascorbate peroxidase (APX) and cytochrome c peroxidase (CcP) have active site structures very similar to KatG and are also capable of activating isoniazid. We report here the first crystal structures of complexes of isoniazid bound to APX and CcP. These are the first structures of isoniazid bound to any activating enzymes. The structures show that isoniazid binds close to the delta-heme edge in both APX and CcP, although the precise binding orientation varies slightly in the two cases. A second binding site for INH is found in APX at the gamma-heme edge close to the established ascorbate binding site, indicating that the gamma-heme edge can also support the binding of aromatic substrates. We also show that in an active site mutant of soybean APX (W41A) INH can bind directly to the heme iron to become an inhibitor and in a different mode when the distal histidine is replaced by alanine (H42A). These structures provide the first unambiguous evidence for the location of the isoniazid binding site in the class I peroxidases and provide rationalization of isoniazid resistance in naturally occurring KatG mutant strains of M. tuberculosis.
About this Structure
2V23 is a Single protein structure of sequence from Saccharomyces cerevisiae with as ligand. Active as Cytochrome-c peroxidase, with EC number 1.11.1.5 Known structural/functional Site: . Full crystallographic information is available from OCA.
Reference
The Tuberculosis Prodrug Isoniazid Bound to Activating Peroxidases., Metcalfe C, Macdonald IK, Murphy EJ, Brown KA, Raven EL, Moody PC, J Biol Chem. 2008 Mar 7;283(10):6193-6200. Epub 2007 Dec 5. PMID:18056997
Page seeded by OCA on Fri Mar 14 09:43:31 2008
Categories: Cytochrome-c peroxidase | Saccharomyces cerevisiae | Single protein | Brown, K A. | Macdonald, I K. | Metcalfe, C L. | Moody, P C.E. | Raven, E L. | HEM | Ccp | Cytochrome c peroxidase | Heme | Hydrogen peroxide | Inh | Iron | Isoniazid | Metal-binding | Mitochondrion | Organic radical | Oxidoreductase | Peroxidase | Transit peptide
