1ywd
From Proteopedia
| Line 1: | Line 1: | ||
[[Image:1ywd.gif|left|200px]] | [[Image:1ywd.gif|left|200px]] | ||
| - | + | <!-- | |
| - | + | The line below this paragraph, containing "STRUCTURE_1ywd", creates the "Structure Box" on the page. | |
| - | + | You may change the PDB parameter (which sets the PDB file loaded into the applet) | |
| - | + | or the SCENE parameter (which sets the initial scene displayed when the page is loaded), | |
| - | + | or leave the SCENE parameter empty for the default display. | |
| - | + | --> | |
| - | + | {{STRUCTURE_1ywd| PDB=1ywd | SCENE= }} | |
| - | + | ||
| - | + | ||
| - | }} | + | |
'''1.08 A Structure of Ferrous NP4 (aquo complex)''' | '''1.08 A Structure of Ferrous NP4 (aquo complex)''' | ||
| Line 29: | Line 26: | ||
[[Category: Roberts, S A.]] | [[Category: Roberts, S A.]] | ||
[[Category: Weichsel, A.]] | [[Category: Weichsel, A.]] | ||
| - | [[Category: | + | [[Category: Beta barrel]] |
| - | [[Category: | + | [[Category: Ferrous heme]] |
| - | [[Category: | + | [[Category: Lipocalin fold]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 16:52:40 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 13:52, 3 May 2008
1.08 A Structure of Ferrous NP4 (aquo complex)
Overview
Nitrophorin 4 (NP4), a nitric oxide (NO)-transport protein from the blood-sucking insect Rhodnius prolixus, uses a ferric (Fe3+) heme to deliver NO to its victims. NO binding to NP4 induces a large conformational change and complete desolvation of the distal pocket. The heme is markedly nonplanar, displaying a ruffling distortion postulated to contribute to stabilization of the ferric iron. Here, we report the ferrous (Fe2+) complexes of NP4 with NO, CO, and H2O formed after chemical reduction of the protein and the characterization of these complexes by absorption spectroscopy, flash photolysis, and ultrahigh-resolution crystallography (resolutions vary from 0.9 to 1.08 A). The absorption spectra, both in solution and in the crystal, are typical for six-coordinated ferrous complexes. Closure and desolvation of the distal pocket occurs upon binding CO or NO to the iron regardless of the heme oxidation state, confirming that the conformational change is driven by distal ligand polarity. The degree of heme ruffling is coupled to the nature of the ligand and the iron oxidation state in the following order: (Fe3+)-NO > (Fe2+)-NO > (Fe2+)-CO > (Fe3+)-H2O > (Fe2+)-H2O. The ferrous coordination geometry is as expected, except for the proximal histidine bond, which is shorter than typically found in model compounds. These data are consistent with heme ruffling and coordination geometry serving to stabilize the ferric state of the nitrophorins, a requirement for their physiological function. Possible roles for heme distortion and NO bending in heme protein function are discussed.
About this Structure
1YWD is a Single protein structure of sequence from Rhodnius prolixus. Full crystallographic information is available from OCA.
Reference
Ultrahigh resolution structures of nitrophorin 4: heme distortion in ferrous CO and NO complexes., Maes EM, Roberts SA, Weichsel A, Montfort WR, Biochemistry. 2005 Sep 27;44(38):12690-9. PMID:16171383 Page seeded by OCA on Sat May 3 16:52:40 2008
