1pl4: Difference between revisions
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New page: left|200px<br /> <applet load="1pl4" size="450" color="white" frame="true" align="right" spinBox="true" caption="1pl4, resolution 1.47Å" /> '''Crystal Structure o... |
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[[Image:1pl4.gif|left|200px]]<br /> | [[Image:1pl4.gif|left|200px]]<br /><applet load="1pl4" size="350" color="white" frame="true" align="right" spinBox="true" | ||
<applet load="1pl4" size=" | |||
caption="1pl4, resolution 1.47Å" /> | caption="1pl4, resolution 1.47Å" /> | ||
'''Crystal Structure of human MnSOD Y166F mutant'''<br /> | '''Crystal Structure of human MnSOD Y166F mutant'''<br /> | ||
==Overview== | ==Overview== | ||
The side chains of His30 and Tyr166 from adjacent subunits in the | The side chains of His30 and Tyr166 from adjacent subunits in the homotetramer human manganese superoxide dismutase (Mn-SOD) form a hydrogen bond across the dimer interface and participate in a hydrogen-bonded network that extends to the active site. Compared with wild-type Mn-SOD, the site-specific mutants H30N, Y166F, and the corresponding double mutant showed 10-fold decreases in steady-state constants for catalysis measured by pulse radiolysis. The observation of no additional effect upon the second mutation is an example of cooperatively interacting residues. A similar effect was observed in the thermal stability of these enzymes; the double mutant did not reduce the major unfolding transition to an extent greater than either single mutant. The crystal structures of these site-specific mutants each have unique conformational changes, but each has lost the hydrogen bond across the dimer interface, which results in a decrease in catalysis. These same mutations caused an enhancement of the dissociation of the product-inhibited complex. That is, His30 and Tyr166 in wild-type Mn-SOD act to prolong the lifetime of the inhibited complex. This would have a selective advantage in blocking a cellular overproduction of toxic H2O2. | ||
==About this Structure== | ==About this Structure== | ||
1PL4 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with MN as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Superoxide_dismutase Superoxide dismutase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.15.1.1 1.15.1.1] Full crystallographic information is available from [http:// | 1PL4 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with <scene name='pdbligand=MN:'>MN</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Superoxide_dismutase Superoxide dismutase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.15.1.1 1.15.1.1] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1PL4 OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Superoxide dismutase]] | [[Category: Superoxide dismutase]] | ||
[[Category: Fan, L.]] | [[Category: Fan, L.]] | ||
[[Category: Tainer, J | [[Category: Tainer, J A.]] | ||
[[Category: MN]] | [[Category: MN]] | ||
[[Category: oxidoreductase]] | [[Category: oxidoreductase]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:29:58 2008'' | ||
