1ch9: Difference between revisions
New page: left|200px<br /><applet load="1ch9" size="450" color="white" frame="true" align="right" spinBox="true" caption="1ch9, resolution 1.80Å" /> '''RECOMBINANT SPERM WH... |
No edit summary |
||
| Line 1: | Line 1: | ||
[[Image:1ch9.jpg|left|200px]]<br /><applet load="1ch9" size=" | [[Image:1ch9.jpg|left|200px]]<br /><applet load="1ch9" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1ch9, resolution 1.80Å" /> | caption="1ch9, resolution 1.80Å" /> | ||
'''RECOMBINANT SPERM WHALE MYOGLOBIN H97Q MUTANT (MET)'''<br /> | '''RECOMBINANT SPERM WHALE MYOGLOBIN H97Q MUTANT (MET)'''<br /> | ||
==Overview== | ==Overview== | ||
The ability of myoglobin to bind oxygen reversibly depends critically on | The ability of myoglobin to bind oxygen reversibly depends critically on retention of the heme prosthetic group. Globin side chains at the Leu(89)(F4), His(97)(FG3), Ile(99)(FG5), and Leu(104)(G5) positions on the proximal side of the heme pocket strongly influence heme affinity. The roles of these amino acids in preventing heme loss have been examined by determining high resolution structures of 14 different mutants at these positions using x-ray crystallography. Leu(89) and His(97) are important surface amino acids that interact either sterically or electrostatically with the edges of the porphyrin ring. Ile(99) and Leu(104) are located in the interior region of the proximal pocket beneath ring C of the heme prosthetic group. The apolar amino acids Leu(89), Ile(99), and Leu(104) "waterproof" the heme pocket by forming a barrier to solvent penetration, minimizing the size of the proximal cavity, and maintaining a hydrophobic environment. Substitutions with smaller or polar side chains at these positions result in exposure of the heme to solvent, the appearance of crystallographically defined water molecules in or near the proximal pocket, and large increases in the rate of hemin loss. Thus, the naturally occurring amino acid side chains at these positions serve to prevent hydration of the His(93)-Fe(III) bond and are highly conserved in all known myoglobins and hemoglobins. | ||
==About this Structure== | ==About this Structure== | ||
1CH9 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Physeter_catodon Physeter catodon] with SO4 and HEM as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | 1CH9 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Physeter_catodon Physeter catodon] 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=1CH9 OCA]. | ||
==Reference== | ==Reference== | ||
| Line 13: | Line 13: | ||
[[Category: Physeter catodon]] | [[Category: Physeter catodon]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Jr., G | [[Category: Jr., G N.Phillips.]] | ||
[[Category: Liong, E | [[Category: Liong, E C.]] | ||
[[Category: HEM]] | [[Category: HEM]] | ||
[[Category: SO4]] | [[Category: SO4]] | ||
| Line 21: | Line 21: | ||
[[Category: oxygen transport]] | [[Category: oxygen transport]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:06:03 2008'' | ||
Revision as of 13:06, 21 February 2008
|
RECOMBINANT SPERM WHALE MYOGLOBIN H97Q MUTANT (MET)
OverviewOverview
The ability of myoglobin to bind oxygen reversibly depends critically on retention of the heme prosthetic group. Globin side chains at the Leu(89)(F4), His(97)(FG3), Ile(99)(FG5), and Leu(104)(G5) positions on the proximal side of the heme pocket strongly influence heme affinity. The roles of these amino acids in preventing heme loss have been examined by determining high resolution structures of 14 different mutants at these positions using x-ray crystallography. Leu(89) and His(97) are important surface amino acids that interact either sterically or electrostatically with the edges of the porphyrin ring. Ile(99) and Leu(104) are located in the interior region of the proximal pocket beneath ring C of the heme prosthetic group. The apolar amino acids Leu(89), Ile(99), and Leu(104) "waterproof" the heme pocket by forming a barrier to solvent penetration, minimizing the size of the proximal cavity, and maintaining a hydrophobic environment. Substitutions with smaller or polar side chains at these positions result in exposure of the heme to solvent, the appearance of crystallographically defined water molecules in or near the proximal pocket, and large increases in the rate of hemin loss. Thus, the naturally occurring amino acid side chains at these positions serve to prevent hydration of the His(93)-Fe(III) bond and are highly conserved in all known myoglobins and hemoglobins.
About this StructureAbout this Structure
1CH9 is a Single protein structure of sequence from Physeter catodon with and as ligands. Full crystallographic information is available from OCA.
ReferenceReference
Waterproofing the heme pocket. Role of proximal amino acid side chains in preventing hemin loss from myoglobin., Liong EC, Dou Y, Scott EE, Olson JS, Phillips GN Jr, J Biol Chem. 2001 Mar 23;276(12):9093-100. Epub 2000 Nov 17. PMID:11084036
Page seeded by OCA on Thu Feb 21 12:06:03 2008