1myi
From Proteopedia
(New page: 200px<br /><applet load="1myi" size="450" color="white" frame="true" align="right" spinBox="true" caption="1myi, resolution 2.0Å" /> '''HIGH RESOLUTION X-RAY...) |
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| - | [[Image:1myi.gif|left|200px]]<br /><applet load="1myi" size=" | + | [[Image:1myi.gif|left|200px]]<br /><applet load="1myi" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1myi, resolution 2.0Å" /> | caption="1myi, resolution 2.0Å" /> | ||
'''HIGH RESOLUTION X-RAY STRUCTURES OF PIG METMYOGLOBIN AND TWO CD3 MUTANTS MB(LYS45-> ARG) AND MB(LYS45-> SER)'''<br /> | '''HIGH RESOLUTION X-RAY STRUCTURES OF PIG METMYOGLOBIN AND TWO CD3 MUTANTS MB(LYS45-> ARG) AND MB(LYS45-> SER)'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The structure of pig aquometmyoglobin has been refined to a | + | The structure of pig aquometmyoglobin has been refined to a crystallographic R-factor of 19.8% against X-ray diffraction data between 10- and 1.75-A spacing. The final structural model comprises two molecules of pig myoglobin, 233 water molecules, and two sulfate ions. A water molecule is coordinated to each of the heme iron atoms with an average Fe-OH2 bond distance of 2.19 A, and the mean Fe-N epsilon (proximal histidine-93) distance is 2.20 A. In contrast to the structure of sperm whale metmyoglobin, the iron is not significantly displaced from the plane of the heme. At the entrance to the heme pocket, the side-chain amino group of lysine-45 (CD3) is well-defined in the electron density map and forms salt-bridging interactions with the heme 6-propionate and with a sulfate ion. Serine and arginine replacements have been made previously at position 45 to examine the proposal that the CD3 side chain acts as a barrier to ligand entry into the protein. Crystal structures of the arginine-45 and serine-45 mutant metmyoglobins have been solved to 1.9 and 2.0 A resolution, respectively. In both cases the structural changes are confined to the site of mutation. Arginine-45 takes up a conformation closely similar to that observed for this residue in wild-type sperm whale myoglobin, in which it makes more extensive charge-charge and charge-dipole interactions and appears to restrict the movement of the distal histidine away from the ligand. The hydroxyl group of serine-45 is disordered, but it is clear that the effect of the mutation is to open up the solvent-exposed face of the heme pocket. |
==About this Structure== | ==About this Structure== | ||
| - | 1MYI is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Sus_scrofa Sus scrofa] with HEM as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http:// | + | 1MYI is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Sus_scrofa Sus scrofa] with <scene name='pdbligand=HEM:'>HEM</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1MYI OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Sus scrofa]] | [[Category: Sus scrofa]] | ||
[[Category: Dauter, Z.]] | [[Category: Dauter, Z.]] | ||
| - | [[Category: Oldfield, T | + | [[Category: Oldfield, T J.]] |
[[Category: Petratos, K.]] | [[Category: Petratos, K.]] | ||
| - | [[Category: Smerdon, S | + | [[Category: Smerdon, S J.]] |
| - | [[Category: Wilkinson, A | + | [[Category: Wilkinson, A J.]] |
| - | [[Category: Wilson, K | + | [[Category: Wilson, K S.]] |
[[Category: HEM]] | [[Category: HEM]] | ||
[[Category: oxygen storage]] | [[Category: oxygen storage]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:00:21 2008'' |
Revision as of 12:00, 21 February 2008
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HIGH RESOLUTION X-RAY STRUCTURES OF PIG METMYOGLOBIN AND TWO CD3 MUTANTS MB(LYS45-> ARG) AND MB(LYS45-> SER)
Overview
The structure of pig aquometmyoglobin has been refined to a crystallographic R-factor of 19.8% against X-ray diffraction data between 10- and 1.75-A spacing. The final structural model comprises two molecules of pig myoglobin, 233 water molecules, and two sulfate ions. A water molecule is coordinated to each of the heme iron atoms with an average Fe-OH2 bond distance of 2.19 A, and the mean Fe-N epsilon (proximal histidine-93) distance is 2.20 A. In contrast to the structure of sperm whale metmyoglobin, the iron is not significantly displaced from the plane of the heme. At the entrance to the heme pocket, the side-chain amino group of lysine-45 (CD3) is well-defined in the electron density map and forms salt-bridging interactions with the heme 6-propionate and with a sulfate ion. Serine and arginine replacements have been made previously at position 45 to examine the proposal that the CD3 side chain acts as a barrier to ligand entry into the protein. Crystal structures of the arginine-45 and serine-45 mutant metmyoglobins have been solved to 1.9 and 2.0 A resolution, respectively. In both cases the structural changes are confined to the site of mutation. Arginine-45 takes up a conformation closely similar to that observed for this residue in wild-type sperm whale myoglobin, in which it makes more extensive charge-charge and charge-dipole interactions and appears to restrict the movement of the distal histidine away from the ligand. The hydroxyl group of serine-45 is disordered, but it is clear that the effect of the mutation is to open up the solvent-exposed face of the heme pocket.
About this Structure
1MYI is a Single protein structure of sequence from Sus scrofa with as ligand. Full crystallographic information is available from OCA.
Reference
High-resolution X-ray structures of pig metmyoglobin and two CD3 mutants: Mb(Lys45----Arg) and Mb(Lys45----Ser)., Oldfield TJ, Smerdon SJ, Dauter Z, Petratos K, Wilson KS, Wilkinson AJ, Biochemistry. 1992 Sep 22;31(37):8732-9. PMID:1390659
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