2ghh: Difference between revisions

Revision as of 05:06, 4 May 2008

Conformational mobility in the active site of a heme peroxidase

OverviewOverview

Conformational mobility of the distal histidine residue has been implicated for several different heme peroxidase enzymes, but unambiguous structural evidence is not available. In this work, we present mechanistic, spectroscopic, and structural evidence for peroxide- and ligand-induced conformational mobility of the distal histidine residue (His-42) in a site-directed variant of ascorbate peroxidase (W41A). In this variant, His-42 binds "on" to the heme in the oxidized form, duplicating the active site structure of the cytochromes b but, in contrast to the cytochromes b, is able to swing "off" the iron during catalysis. This conformational flexibility between the on and off forms is fully reversible and is used as a means to overcome the inherently unreactive nature of the on form toward peroxide, so that essentially complete catalytic activity is maintained. Contrary to the widely adopted view of heme enzyme catalysis, these data indicate that strong coordination of the distal histidine to the heme iron does not automatically undermine catalytic activity. The data add a new dimension to our wider appreciation of structure/activity correlations in other heme enzymes.

About this StructureAbout this Structure

2GHH is a Single protein structure of sequence from Glycine max. Full crystallographic information is available from OCA.

ReferenceReference

Conformational mobility in the active site of a heme peroxidase., Badyal SK, Joyce MG, Sharp KH, Seward HE, Mewies M, Basran J, Macdonald IK, Moody PC, Raven EL, J Biol Chem. 2006 Aug 25;281(34):24512-20. Epub 2006 Jun 7. PMID:16762924 Page seeded by OCA on Sun May 4 05:06:45 2008

Proteopedia Page Contributors and Editors (what is this?)Proteopedia Page Contributors and Editors (what is this?)

OCA

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 [[Image:2ghh.gif|left|200px]]
- {{Structure
+<!--
-|PDB= 2ghh |SIZE=350|CAPTION= <scene name='initialview01'>2ghh</scene>, resolution 2.013&Aring;
+The line below this paragraph, containing "STRUCTURE_2ghh", creates the "Structure Box" on the page.
-|SITE=
+You may change the PDB parameter (which sets the PDB file loaded into the applet)
-|LIGAND= <scene name='pdbligand=HEM:PROTOPORPHYRIN+IX+CONTAINING+FE'>HEM</scene>, <scene name='pdbligand=K:POTASSIUM+ION'>K</scene>, <scene name='pdbligand=NO:NITROGEN+OXIDE'>NO</scene>
+or the SCENE parameter (which sets the initial scene displayed when the page is loaded),
-|ACTIVITY= <span class='plainlinks'>[http://en.wikipedia.org/wiki/L-ascorbate_peroxidase L-ascorbate peroxidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.11.1.11 1.11.1.11] </span>
+or leave the SCENE parameter empty for the default display.
-|GENE= ascorbate peroxidase ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=3847 Glycine max])
+-->
-|DOMAIN=
+{{STRUCTURE_2ghh|  PDB=2ghh  |  SCENE=  }}
-|RELATEDENTRY=[[2ggn|2GGN]], [[2ghc|2GHC]], [[2ghd|2GHD]], [[2ghe|2GHE]], [[2ghk|2GHK]]
-|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2ghh FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2ghh OCA], [http://www.ebi.ac.uk/pdbsum/2ghh PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=2ghh RCSB]</span>
-}}
 '''Conformational mobility in the active site of a heme peroxidase'''
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 [[Category: Raven, E L.]]
 [[Category: Sharp, K H.]]
-[[Category: orthogonal bundle]]
+[[Category: Orthogonal bundle]]
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May  4 05:06:45 2008''
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Mar 31 03:16:44 2008''