1oah: Difference between revisions

Revision as of 15:13, 5 November 2007

CYTOCHROME C NITRITE REDUCTASE FROM DESULFOVIBRIO DESULFURICANS ATCC 27774: THE RELEVANCE OF THE TWO CALCIUM SITES IN THE STRUCTURE OF THE CATALYTIC SUBUNIT (NRFA).

OverviewOverview

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 StructureAbout 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.

ReferenceReference

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

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 ==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 ... [[http://ispc.weizmann.ac.il/pmbin/getpm?12618432 (full description)]]
+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==
-OAH 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]].
+OAH 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==
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 [[Category: respiratory nitrite ammonification]]
-''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Tue Oct 30 15:48:10 2007''
+''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov  5 14:19:16 2007''