This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.

Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.


1mni

From Proteopedia

(Difference between revisions)
Jump to: navigation, search
Line 1: Line 1:
-
[[Image:1mni.jpg|left|200px]]
+
{{Seed}}
 +
[[Image:1mni.png|left|200px]]
<!--
<!--
Line 9: Line 10:
{{STRUCTURE_1mni| PDB=1mni | SCENE= }}
{{STRUCTURE_1mni| PDB=1mni | SCENE= }}
-
'''ALTERATION OF AXIAL COORDINATION BY PROTEIN ENGINEERING IN MYOGLOBIN. BIS-IMIDAZOLE LIGATION IN THE HIS64-->VAL(SLASH)VAL68-->HIS DOUBLE MUTANT'''
+
===ALTERATION OF AXIAL COORDINATION BY PROTEIN ENGINEERING IN MYOGLOBIN. BIS-IMIDAZOLE LIGATION IN THE HIS64-->VAL(SLASH)VAL68-->HIS DOUBLE MUTANT===
-
==Overview==
+
<!--
-
Pig and human myoglobin have been engineered to reverse the positions of the distal histidine and valine (i.e. His64(E7)--&gt;Val and Val68(E11)--&gt;His). Spectroscopic and ligand binding properties have been measured for human and pig H64V/V68H myoglobin, and the structure of the pig H64V/V68H double mutant has been determined to 2.07-A resolution by x-ray crystallography. The crystal structure shows that the N epsilon of His68 is located 2.3 A away from the heme iron, resulting in the formation of a hexacoordinate species. The imidazole plane of His68 is tilted relative to the heme normal; moreover it is not parallel to that of His93, in agreement with our previous proposal (Qin, J., La Mar, G. N., Dou, Y., Admiraal, S. J., and Ikeda-Saito, M. (1994) J. Biol. Chem. 269, 1083-1090). At cryogenic temperatures, the heme iron is in a low spin state, which exhibits a highly anisotropic EPR spectrum (g1 = 3.34, g2 = 2.0, and g3 &lt; 1), quite different from that of the imidazole complex of metmyoglobin. The mean iron-nitrogen distance is 2.01 A for the low spin ferric state as determined by x-ray spectroscopy. The ferrous form of H64V/V68H myoglobin shows an optical spectrum that is similar to that of b-type cytochromes and consistent with the hexacoordinate bisimidazole hemin structure determined by the x-ray crystallography. The double mutation lowers the ferric/ferrous couple midpoint potential from +54 mV of the wild-type protein to -128 mV. Ferrous H64V/V68H myoglobin binds CO and NO to form stable complexes, but its reaction with O2 results in a rapid autooxidation to the ferric species. All of these results demonstrate that the three-dimensional positions of His64 and Val68 in the wild-type myoglobin are as important as the chemical nature of the side chains in facilitating reversible O2 binding and inhibiting autooxidation.
+
The line below this paragraph, {{ABSTRACT_PUBMED_7608158}}, adds the Publication Abstract to the page
 +
(as it appears on PubMed at http://www.pubmed.gov), where 7608158 is the PubMed ID number.
 +
-->
 +
{{ABSTRACT_PUBMED_7608158}}
==About this Structure==
==About this Structure==
Line 25: Line 29:
[[Category: Wilkinson, A J.]]
[[Category: Wilkinson, A J.]]
[[Category: Oxygen storage]]
[[Category: Oxygen storage]]
-
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 01:27:52 2008''
+
 
 +
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Jul 3 00:28:24 2008''

Revision as of 21:28, 2 July 2008

Image:1mni.png

Template:STRUCTURE 1mni

ALTERATION OF AXIAL COORDINATION BY PROTEIN ENGINEERING IN MYOGLOBIN. BIS-IMIDAZOLE LIGATION IN THE HIS64-->VAL(SLASH)VAL68-->HIS DOUBLE MUTANT

Template:ABSTRACT PUBMED 7608158

About this Structure

1MNI is a Single protein structure of sequence from Sus scrofa. Full crystallographic information is available from OCA.

Reference

Alteration of axial coordination by protein engineering in myoglobin. Bisimidazole ligation in the His64-->Val/Val68-->His double mutant., Dou Y, Admiraal SJ, Ikeda-Saito M, Krzywda S, Wilkinson AJ, Li T, Olson JS, Prince RC, Pickering IJ, George GN, J Biol Chem. 1995 Jul 7;270(27):15993-6001. PMID:7608158

Page seeded by OCA on Thu Jul 3 00:28:24 2008

Proteopedia Page Contributors and Editors (what is this?)

OCA

Retrieved from "http://52.214.119.220/wiki/index.php/1mni"
Personal tools