2cah
From Proteopedia
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==Overview== | ==Overview== | ||
| - | A catalase from a peroxide resistant mutant of Proteus mirabilis binds, NADPH tightly. Interestingly, this enzyme can be stripped of NADPH without, loss of the catalatic activity. It is the only known non-mammalian, catalase able to bind NADPH. The structure without cofactor was solved by, molecular replacement using the structure of beef liver catalase as a, model. The structure was refined to an R-factor of 19.3% in the range 8 to, 2.2 A resolution. According to the sequence, a methionine sulphone was, positioned in the haem active site. This oxidized form of methionine is, particular to Proteus mirabilis catalase and likely to produce some steric, hindrance in the active site. Two important water molecules are positioned, in the haem distal site. These two water molecules are not ... | + | A catalase from a peroxide resistant mutant of Proteus mirabilis binds, NADPH tightly. Interestingly, this enzyme can be stripped of NADPH without, loss of the catalatic activity. It is the only known non-mammalian, catalase able to bind NADPH. The structure without cofactor was solved by, molecular replacement using the structure of beef liver catalase as a, model. The structure was refined to an R-factor of 19.3% in the range 8 to, 2.2 A resolution. According to the sequence, a methionine sulphone was, positioned in the haem active site. This oxidized form of methionine is, particular to Proteus mirabilis catalase and likely to produce some steric, hindrance in the active site. Two important water molecules are positioned, in the haem distal site. These two water molecules are not located in the, structure of beef liver catalase, but are supposed to account for the, catalytic mechanism. The liganded form was obtained by soaking crystals of, the unliganded form into an NADPH solution. The structure was refined to, an R-factor of 15.9% in the range of 8 to 3.1 A resolution using the, unliganded structure as a model. The NADPH was clearly located in the, electron density map with the same conformation as in beef liver catalase., The NADPH binding induces slight structural changes. However, the, imidazole ring of a histidine residue (His284) rotates about 50 degrees to, accommodate the cofactor. The electron transfer from NADPH to the haem, molecule was examined and several pathways are proposed. |
==About this Structure== | ==About this Structure== | ||
| - | 2CAH is a | + | 2CAH is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Proteus_mirabilis Proteus mirabilis] with HEM and NDP as [http://en.wikipedia.org/wiki/ligands ligands]. This structure superseeds the now removed PDB entry 1CAF. 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] Structure known Active Sites: 337 and 54. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=2CAH OCA]. |
==Reference== | ==Reference== | ||
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[[Category: peroxidase]] | [[Category: peroxidase]] | ||
| - | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 5 15:32:57 2007'' |
Revision as of 13:27, 5 November 2007
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STRUCTURE OF PROTEUS MIRABILIS PR CATALASE FOR THE NATIVE FORM (E-FE(III)) COMPLEXED WITH NADPH
Overview
A catalase from a peroxide resistant mutant of Proteus mirabilis binds, NADPH tightly. Interestingly, this enzyme can be stripped of NADPH without, loss of the catalatic activity. It is the only known non-mammalian, catalase able to bind NADPH. The structure without cofactor was solved by, molecular replacement using the structure of beef liver catalase as a, model. The structure was refined to an R-factor of 19.3% in the range 8 to, 2.2 A resolution. According to the sequence, a methionine sulphone was, positioned in the haem active site. This oxidized form of methionine is, particular to Proteus mirabilis catalase and likely to produce some steric, hindrance in the active site. Two important water molecules are positioned, in the haem distal site. These two water molecules are not located in the, structure of beef liver catalase, but are supposed to account for the, catalytic mechanism. The liganded form was obtained by soaking crystals of, the unliganded form into an NADPH solution. The structure was refined to, an R-factor of 15.9% in the range of 8 to 3.1 A resolution using the, unliganded structure as a model. The NADPH was clearly located in the, electron density map with the same conformation as in beef liver catalase., The NADPH binding induces slight structural changes. However, the, imidazole ring of a histidine residue (His284) rotates about 50 degrees to, accommodate the cofactor. The electron transfer from NADPH to the haem, molecule was examined and several pathways are proposed.
About this Structure
2CAH is a Single protein structure of sequence from Proteus mirabilis with HEM and NDP as ligands. This structure superseeds the now removed PDB entry 1CAF. Active as Catalase, with EC number 1.11.1.6 Structure known Active Sites: 337 and 54. Full crystallographic information is available from OCA.
Reference
Crystal structure of Proteus mirabilis PR catalase with and without bound NADPH., Gouet P, Jouve HM, Dideberg O, J Mol Biol. 1995 Jun 23;249(5):933-54. PMID:7791219
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