1luv
From Proteopedia
(New page: 200px<br /> <applet load="1luv" size="450" color="white" frame="true" align="right" spinBox="true" caption="1luv, resolution 1.85Å" /> '''CATALYTIC AND STRUC...) |
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caption="1luv, resolution 1.85Å" /> | caption="1luv, resolution 1.85Å" /> | ||
'''CATALYTIC AND STRUCTURAL EFFECTS OF AMINO-ACID SUBSTITUTION AT HIS 30 IN HUMAN MANGANESE SUPEROXIDE DISMUTASE: INSERTION OF VAL CGAMMA INTO THE SUBSTRATE ACCESS CHANNEL'''<br /> | '''CATALYTIC AND STRUCTURAL EFFECTS OF AMINO-ACID SUBSTITUTION AT HIS 30 IN HUMAN MANGANESE SUPEROXIDE DISMUTASE: INSERTION OF VAL CGAMMA INTO THE SUBSTRATE ACCESS CHANNEL'''<br /> | ||
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==About this Structure== | ==About this Structure== | ||
| - | 1LUV 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:// | + | 1LUV 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=1LUV OCA]. |
==Reference== | ==Reference== | ||
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[[Category: wild type]] | [[Category: wild type]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri Feb 15 16:20:30 2008'' |
Revision as of 14:20, 15 February 2008
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CATALYTIC AND STRUCTURAL EFFECTS OF AMINO-ACID SUBSTITUTION AT HIS 30 IN HUMAN MANGANESE SUPEROXIDE DISMUTASE: INSERTION OF VAL CGAMMA INTO THE SUBSTRATE ACCESS CHANNEL
Overview
Catalysis of the disproportionation of superoxide by human manganese, superoxide dismutase (MnSOD) is characterized by an initial burst of, catalysis followed by a much slower region that is zero order in, superoxide and due to a product inhibition by peroxide anion. We have, prepared site-specific mutants with replacements at His30, the side chain, of which lies along the substrate access channel and is about 5.8 A from, the metal. Using pulse radiolysis to generate superoxide, we have, determined that kcat/K(m) was decreased and product inhibition increased, for H30V MnSOD, both by 1-2 orders of magnitude, compared with wild type, H30N, and H30Q MnSOD. These effects are not attributed to the redox, potentials, which are similar for all of these variants. An investigation, of the crystal structure of H30V Mn(III)SOD compared with wild type, H30Q, and H30N Mn(III)SOD showed the positions of two gamma carbons of Val30 in, the active site; Cgamma1 overlaps Cgamma of His30 in wild type, and, Cgamma2 extends into the substrate access channel and occupies the, approximate position of a water molecule in the wild type. The data, suggest that Cgamma2 of the Val side chain has significantly interrupted, catalysis by this overlap into the access channel with possible overlap, with the substrate-product binding site. This is supported by comparison, of the crystal structure of H30V MnSOD with that of azide bound to, Mn(III)SOD from Thermus thermophilus and by visible absorption spectra, showing that azide binding to the metal in H30V Mn(III)SOD is abolished., Moreover, the presence of Val30 caused a 100-fold decrease in the rate, constant for dissociation of the product-inhibited complex compared with, wild type.
About this Structure
1LUV is a Single protein structure of sequence from Homo sapiens with as ligand. Active as Superoxide dismutase, with EC number 1.15.1.1 Full crystallographic information is available from OCA.
Reference
Catalytic and structural effects of amino acid substitution at histidine 30 in human manganese superoxide dismutase: insertion of valine C gamma into the substrate access channel., Hearn AS, Stroupe ME, Cabelli DE, Ramilo CA, Luba JP, Tainer JA, Nick HS, Silverman DN, Biochemistry. 2003 Mar 18;42(10):2781-9. PMID:12627943
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