1nz4: Difference between revisions
New page: left|200px<br /><applet load="1nz4" size="450" color="white" frame="true" align="right" spinBox="true" caption="1nz4, resolution 1.8Å" /> '''The horse heart myogl... |
No edit summary |
||
| Line 1: | Line 1: | ||
[[Image:1nz4.jpg|left|200px]]<br /><applet load="1nz4" size=" | [[Image:1nz4.jpg|left|200px]]<br /><applet load="1nz4" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1nz4, resolution 1.8Å" /> | caption="1nz4, resolution 1.8Å" /> | ||
'''The horse heart myoglobin variant K45E/K63E complexed with Cadmium'''<br /> | '''The horse heart myoglobin variant K45E/K63E complexed with Cadmium'''<br /> | ||
==Overview== | ==Overview== | ||
A binding site for metal ions has been created on the surface of horse | A binding site for metal ions has been created on the surface of horse heart myoglobin (Mb) near the heme 6-propionate group by replacing K45 and K63 with glutamyl residues. One-dimensional (1)H NMR spectroscopy indicates that Mn(2+) binds in the vicinity of the heme 6-propionate as anticipated, and potentiometric titrations establish that the affinity of the new site for Mn(2+) is 1.28(4) x 10(4) M(-1) (pH 6.96, ionic strength I = 17.2 microM, 25 degrees C). In addition, these substitutions lower the reduction potential of the protein and increase the pK(a) for the water molecule coordinated to the heme iron of metmyoglobin. The peroxidase [2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid), ABTS, as substrate] and the Mn(2+)-peroxidase activity of the variant are both increased approximately 3-fold. In contrast to wild-type Mb, both the affinity for azide and the midpoint potential of the variant are significantly influenced by the addition of Mn(2+). The structure of the variant has been determined by x-ray crystallography to define the coordination environment of bound Mn(2+) and Cd(2+). Although slight differences are observed between the geometry of the binding of the two metal ions, both are hexacoordinate, and neither involves coordination by E63. | ||
==About this Structure== | ==About this Structure== | ||
1NZ4 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Equus_caballus Equus caballus] with CD and HEM as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | 1NZ4 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Equus_caballus Equus caballus] with <scene name='pdbligand=CD:'>CD</scene> and <scene name='pdbligand=HEM:'>HEM</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1NZ4 OCA]. | ||
==Reference== | ==Reference== | ||
| Line 13: | Line 13: | ||
[[Category: Equus caballus]] | [[Category: Equus caballus]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Brayer, G | [[Category: Brayer, G D.]] | ||
[[Category: Hunter, C | [[Category: Hunter, C L.]] | ||
[[Category: Lee, H.]] | [[Category: Lee, H.]] | ||
[[Category: Mauk, A | [[Category: Mauk, A G.]] | ||
[[Category: Mauk, M | [[Category: Mauk, M R.]] | ||
[[Category: Maurus, R.]] | [[Category: Maurus, R.]] | ||
[[Category: Nguyen, N.]] | [[Category: Nguyen, N.]] | ||
[[Category: Raven, E | [[Category: Raven, E L.]] | ||
[[Category: Smith, S.]] | [[Category: Smith, S.]] | ||
[[Category: Tong, H.]] | [[Category: Tong, H.]] | ||
| Line 27: | Line 27: | ||
[[Category: cadmium cd2+ horse heart myoglobin engineered metal binding site]] | [[Category: cadmium cd2+ horse heart myoglobin engineered metal binding site]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:11:38 2008'' | ||
Revision as of 15:11, 21 February 2008
|
The horse heart myoglobin variant K45E/K63E complexed with Cadmium
OverviewOverview
A binding site for metal ions has been created on the surface of horse heart myoglobin (Mb) near the heme 6-propionate group by replacing K45 and K63 with glutamyl residues. One-dimensional (1)H NMR spectroscopy indicates that Mn(2+) binds in the vicinity of the heme 6-propionate as anticipated, and potentiometric titrations establish that the affinity of the new site for Mn(2+) is 1.28(4) x 10(4) M(-1) (pH 6.96, ionic strength I = 17.2 microM, 25 degrees C). In addition, these substitutions lower the reduction potential of the protein and increase the pK(a) for the water molecule coordinated to the heme iron of metmyoglobin. The peroxidase [2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid), ABTS, as substrate] and the Mn(2+)-peroxidase activity of the variant are both increased approximately 3-fold. In contrast to wild-type Mb, both the affinity for azide and the midpoint potential of the variant are significantly influenced by the addition of Mn(2+). The structure of the variant has been determined by x-ray crystallography to define the coordination environment of bound Mn(2+) and Cd(2+). Although slight differences are observed between the geometry of the binding of the two metal ions, both are hexacoordinate, and neither involves coordination by E63.
About this StructureAbout this Structure
1NZ4 is a Single protein structure of sequence from Equus caballus with and as ligands. Full crystallographic information is available from OCA.
ReferenceReference
Introduction and characterization of a functionally linked metal ion binding site at the exposed heme edge of myoglobin., Hunter CL, Maurus R, Mauk MR, Lee H, Raven EL, Tong H, Nguyen N, Smith M, Brayer GD, Mauk AG, Proc Natl Acad Sci U S A. 2003 Apr 1;100(7):3647-52. Epub 2003 Mar 18. PMID:12644706
Page seeded by OCA on Thu Feb 21 14:11:38 2008