1oah: Difference between revisions

Revision as of 15:15, 21 February 2008

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 , , and as ligands. Active as Nitrite reductase (cytochrome; ammonia-forming), with EC number 1.7.2.2 Known structural/functional Site: . 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

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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 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.
+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==
@@ Line 16: / Line 16: @@
 [[Category: Almeida, G.]]
 [[Category: Costa, C.]]
-[[Category: Cunha, C.A.]]
+[[Category: Cunha, C A.]]
-[[Category: Dias, J.M.]]
+[[Category: Dias, J M.]]
-[[Category: Goncalves, L.L.]]
+[[Category: Goncalves, L L.]]
 [[Category: Huber, R.]]
 [[Category: Lampreia, J.]]
 [[Category: Macieira, S.]]
 [[Category: Moura, I.]]
-[[Category: Moura, J.J.G.]]
+[[Category: Moura, J J.G.]]
-[[Category: Romao, M.J.]]
+[[Category: Romao, M J.]]
 [[Category: CA]]
 [[Category: CL]]
@@ Line 34: / Line 34: @@
 [[Category: respiratory nitrite ammonification]]
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Feb  3 09:55:34 2008''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:15:27 2008''