1sy7: Difference between revisions

Revision as of 16:07, 21 February 2008

Crystal structure of the catalase-1 from Neurospora crassa, native structure at 1.75A resolution.

OverviewOverview

Catalase-1, one of four catalase activities of Neurospora crassa, is associated with non-growing cells and accumulates in asexual spores. It is a large, tetrameric, highly efficient, and durable enzyme that is active even at molar concentrations of hydrogen peroxide. Catalase-1 is oxidized at the heme by singlet oxygen without significant effects on enzyme activity. Here we present the crystal structure of catalase-1 at 1.75A resolution. Compared to structures of other catalases of the large class, the main differences were found at the carboxy-terminal domain. The heme group is rotated 180 degrees around the alpha-gamma-meso carbon axis with respect to clade 3 small catalases. There is no co-ordination bond of the ferric ion at the heme distal side in catalase-1. The catalase-1 structure exhibited partial oxidation of heme b to heme d. Singlet oxygen, produced catalytically or by photosensitization, may hydroxylate C5 and C6 of pyrrole ring III with a subsequent formation of a gamma-spirolactone in C6. The modification site in catalases depends on the way dioxygen exits the protein: mainly through the central channel or the main channel in large and small catalases, respectively. The catalase-1 structure revealed an unusual covalent bond between a cysteine sulphur atom and the essential tyrosine residue of the proximal side of the active site. A peptide with the predicted theoretical mass of the two bound tryptic peptides was detected by mass spectrometry. A mechanism for the Cys-Tyr covalent bond formation is proposed. The tyrosine bound to the cysteine residue would be less prone to donate electrons to compound I to form compound II, explaining catalase-1 resistance to substrate inhibition and inactivation. An apparent constriction of the main channel at Ser198 lead us to propose a gate that opens the narrow part of the channel when there is sufficient hydrogen peroxide in the small cavity before the gate. This mechanism would explain the increase in catalytic velocity as the hydrogen peroxide concentration rises.

About this StructureAbout this Structure

1SY7 is a Single protein structure of sequence from Neurospora crassa with and as ligands. Active as Catalase, with EC number 1.11.1.6 Full crystallographic information is available from OCA.

ReferenceReference

Unusual Cys-Tyr covalent bond in a large catalase., Diaz A, Horjales E, Rudino-Pinera E, Arreola R, Hansberg W, J Mol Biol. 2004 Sep 17;342(3):971-85. PMID:15342250

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-[[Image:1sy7.gif|left|200px]]<br /><applet load="1sy7" size="450" color="white" frame="true" align="right" spinBox="true"
+[[Image:1sy7.gif|left|200px]]<br /><applet load="1sy7" size="350" color="white" frame="true" align="right" spinBox="true"
 caption="1sy7, resolution 1.75&Aring;" />
 '''Crystal structure of the catalase-1 from Neurospora crassa, native structure at 1.75A resolution.'''<br />
 ==Overview==
-Catalase-1, one of four catalase activities of Neurospora crassa, is, associated with non-growing cells and accumulates in asexual spores. It is, a large, tetrameric, highly efficient, and durable enzyme that is active, even at molar concentrations of hydrogen peroxide. Catalase-1 is oxidized, at the heme by singlet oxygen without significant effects on enzyme, activity. Here we present the crystal structure of catalase-1 at 1.75A, resolution. Compared to structures of other catalases of the large class, the main differences were found at the carboxy-terminal domain. The heme, group is rotated 180 degrees around the alpha-gamma-meso carbon axis with, respect to clade 3 small catalases. There is no co-ordination bond of the, ferric ion at the heme distal side in catalase-1. The catalase-1 structure, exhibited partial oxidation of heme b to heme d. Singlet oxygen, produced, catalytically or by photosensitization, may hydroxylate C5 and C6 of, pyrrole ring III with a subsequent formation of a gamma-spirolactone in, C6. The modification site in catalases depends on the way dioxygen exits, the protein: mainly through the central channel or the main channel in, large and small catalases, respectively. The catalase-1 structure revealed, an unusual covalent bond between a cysteine sulphur atom and the essential, tyrosine residue of the proximal side of the active site. A peptide with, the predicted theoretical mass of the two bound tryptic peptides was, detected by mass spectrometry. A mechanism for the Cys-Tyr covalent bond, formation is proposed. The tyrosine bound to the cysteine residue would be, less prone to donate electrons to compound I to form compound II, explaining catalase-1 resistance to substrate inhibition and inactivation., An apparent constriction of the main channel at Ser198 lead us to propose, a gate that opens the narrow part of the channel when there is sufficient, hydrogen peroxide in the small cavity before the gate. This mechanism, would explain the increase in catalytic velocity as the hydrogen peroxide, concentration rises.
+Catalase-1, one of four catalase activities of Neurospora crassa, is associated with non-growing cells and accumulates in asexual spores. It is a large, tetrameric, highly efficient, and durable enzyme that is active even at molar concentrations of hydrogen peroxide. Catalase-1 is oxidized at the heme by singlet oxygen without significant effects on enzyme activity. Here we present the crystal structure of catalase-1 at 1.75A resolution. Compared to structures of other catalases of the large class, the main differences were found at the carboxy-terminal domain. The heme group is rotated 180 degrees around the alpha-gamma-meso carbon axis with respect to clade 3 small catalases. There is no co-ordination bond of the ferric ion at the heme distal side in catalase-1. The catalase-1 structure exhibited partial oxidation of heme b to heme d. Singlet oxygen, produced catalytically or by photosensitization, may hydroxylate C5 and C6 of pyrrole ring III with a subsequent formation of a gamma-spirolactone in C6. The modification site in catalases depends on the way dioxygen exits the protein: mainly through the central channel or the main channel in large and small catalases, respectively. The catalase-1 structure revealed an unusual covalent bond between a cysteine sulphur atom and the essential tyrosine residue of the proximal side of the active site. A peptide with the predicted theoretical mass of the two bound tryptic peptides was detected by mass spectrometry. A mechanism for the Cys-Tyr covalent bond formation is proposed. The tyrosine bound to the cysteine residue would be less prone to donate electrons to compound I to form compound II, explaining catalase-1 resistance to substrate inhibition and inactivation. An apparent constriction of the main channel at Ser198 lead us to propose a gate that opens the narrow part of the channel when there is sufficient hydrogen peroxide in the small cavity before the gate. This mechanism would explain the increase in catalytic velocity as the hydrogen peroxide concentration rises.
 ==About this Structure==
-SY7 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Neurospora_crassa Neurospora crassa] with HDD and HEM as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Catalase Catalase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.11.1.6 1.11.1.6] Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1SY7 OCA].
+SY7 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Neurospora_crassa Neurospora crassa] with <scene name='pdbligand=HDD:'>HDD</scene> and <scene name='pdbligand=HEM:'>HEM</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Catalase Catalase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.11.1.6 1.11.1.6] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1SY7 OCA].
 ==Reference==
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 [[Category: singlet oxygen]]
-''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Wed Nov 21 02:50:25 2007''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:07:02 2008''