1myh: Difference between revisions

Revision as of 15:00, 21 February 2008

HIGH RESOLUTION X-RAY STRUCTURES OF PIG METMYOGLOBIN AND TWO CD3 MUTANTS MB(LYS45-> ARG) AND MB(LYS45-> SER)

OverviewOverview

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 StructureAbout this Structure

1MYH is a Single protein structure of sequence from Sus scrofa with and as ligands. Full crystallographic information is available from OCA.

ReferenceReference

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

Page seeded by OCA on Thu Feb 21 14:00:24 2008

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

OCA

@@ Line 1: / Line 1: @@
-[[Image:1myh.gif|left|200px]]<br /><applet load="1myh" size="450" color="white" frame="true" align="right" spinBox="true"
+[[Image:1myh.gif|left|200px]]<br /><applet load="1myh" size="350" color="white" frame="true" align="right" spinBox="true"
 caption="1myh, resolution 1.9&Aring;" />
 '''HIGH RESOLUTION X-RAY STRUCTURES OF PIG METMYOGLOBIN AND TWO CD3 MUTANTS MB(LYS45-> ARG) AND MB(LYS45-> SER)'''<br />
 ==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.
+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==
-MYH 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 SO4 and HEM as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1MYH OCA].
+MYH 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=SO4:'>SO4</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=1MYH OCA].
 ==Reference==
@@ Line 14: / Line 14: @@
 [[Category: Sus scrofa]]
 [[Category: Dauter, Z.]]
-[[Category: Oldfield, T.J.]]
+[[Category: Oldfield, T J.]]
 [[Category: Petratos, K.]]
-[[Category: Smerdon, S.J.]]
+[[Category: Smerdon, S J.]]
-[[Category: Wilkinson, A.J.]]
+[[Category: Wilkinson, A J.]]
-[[Category: Wilson, K.S.]]
+[[Category: Wilson, K S.]]
 [[Category: HEM]]
 [[Category: SO4]]
 [[Category: oxygen storage]]
-''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Tue Nov 20 21:48:37 2007''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:00:24 2008''