1oah
From Proteopedia
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==Overview== | ==Overview== | ||
| - | The gene encoding cytochrome c nitrite reductase (NrfA) from Desulfovibrio, desulfuricans ATCC 27774 was sequenced and the crystal structure of the, enzyme was determined to 2.3-A resolution. In comparison with homologous, structures, it presents structural differences mainly located at the, regions surrounding the putative substrate inlet and product outlet, and, includes a well defined second calcium site with octahedral geometry, coordinated to propionates of hemes 3 and 4, and caged by a loop, non-existent in the previous structures. The highly negative electrostatic, potential in the environment around hemes 3 and 4 suggests that the main, role of this calcium ion may not be electrostatic but structural, namely, in the stabilization of the conformation of the additional loop that ... | + | The gene encoding cytochrome c nitrite reductase (NrfA) from Desulfovibrio, desulfuricans ATCC 27774 was sequenced and the crystal structure of the, enzyme was determined to 2.3-A resolution. In comparison with homologous, structures, it presents structural differences mainly located at the, regions surrounding the putative substrate inlet and product outlet, and, includes a well defined second calcium site with octahedral geometry, coordinated to propionates of hemes 3 and 4, and caged by a loop, non-existent in the previous structures. The highly negative electrostatic, potential in the environment around hemes 3 and 4 suggests that the main, role of this calcium ion may not be electrostatic but structural, namely, in the stabilization of the conformation of the additional loop that cages, it and influences the solvent accessibility of heme 4. The NrfA active, site is similar to that of peroxidases with a nearby calcium site at the, heme distal side nearly in the same location as occurs in the class II and, class III peroxidases. This fact suggests that the calcium ion at the, distal side of the active site in the NrfA enzymes may have a similar, physiological role to that reported for the peroxidases. |
==About this Structure== | ==About this Structure== | ||
| - | 1OAH is a | + | 1OAH is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Desulfovibrio_desulfuricans Desulfovibrio desulfuricans] with CA, CL, ZN and HEM as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Nitrite_reductase_(cytochrome;_ammonia-forming) Nitrite reductase (cytochrome; ammonia-forming)], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.7.2.2 1.7.2.2] Structure known Active Site: AC1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1OAH OCA]. |
==Reference== | ==Reference== | ||
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[[Category: respiratory nitrite ammonification]] | [[Category: respiratory nitrite ammonification]] | ||
| - | ''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 14:19:16 2007'' |
Revision as of 12:13, 5 November 2007
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CYTOCHROME C NITRITE REDUCTASE FROM DESULFOVIBRIO DESULFURICANS ATCC 27774: THE RELEVANCE OF THE TWO CALCIUM SITES IN THE STRUCTURE OF THE CATALYTIC SUBUNIT (NRFA).
Overview
The gene encoding cytochrome c nitrite reductase (NrfA) from Desulfovibrio, desulfuricans ATCC 27774 was sequenced and the crystal structure of the, enzyme was determined to 2.3-A resolution. In comparison with homologous, structures, it presents structural differences mainly located at the, regions surrounding the putative substrate inlet and product outlet, and, includes a well defined second calcium site with octahedral geometry, coordinated to propionates of hemes 3 and 4, and caged by a loop, non-existent in the previous structures. The highly negative electrostatic, potential in the environment around hemes 3 and 4 suggests that the main, role of this calcium ion may not be electrostatic but structural, namely, in the stabilization of the conformation of the additional loop that cages, it and influences the solvent accessibility of heme 4. The NrfA active, site is similar to that of peroxidases with a nearby calcium site at the, heme distal side nearly in the same location as occurs in the class II and, class III peroxidases. This fact suggests that the calcium ion at the, distal side of the active site in the NrfA enzymes may have a similar, physiological role to that reported for the peroxidases.
About this Structure
1OAH is a Single protein structure of sequence from Desulfovibrio desulfuricans with CA, CL, ZN and HEM as ligands. Active as Nitrite reductase (cytochrome; ammonia-forming), with EC number 1.7.2.2 Structure known Active Site: AC1. Full crystallographic information is available from OCA.
Reference
Cytochrome c nitrite reductase from Desulfovibrio desulfuricans ATCC 27774. The relevance of the two calcium sites in the structure of the catalytic subunit (NrfA)., Cunha CA, Macieira S, Dias JM, Almeida G, Goncalves LL, Costa C, Lampreia J, Huber R, Moura JJ, Moura I, Romao MJ, J Biol Chem. 2003 May 9;278(19):17455-65. Epub 2003 Mar 4. PMID:12618432
Page seeded by OCA on Mon Nov 5 14:19:16 2007
Categories: Desulfovibrio desulfuricans | Nitrite reductase (cytochrome; ammonia-forming) | Single protein | Almeida, G. | Costa, C. | Cunha, C.A. | Dias, J.M. | Goncalves, L.L. | Huber, R. | Lampreia, J. | Macieira, S. | Moura, I. | Moura, J.J.G. | Romao, M.J. | CA | CL | HEM | ZN | Cytochrome c | Nitrite reductase | Nitrogen cycle | Respiratory nitrite ammonification
