1hqx
From Proteopedia
(New page: 200px<br /><applet load="1hqx" size="450" color="white" frame="true" align="right" spinBox="true" caption="1hqx, resolution 3.Å" /> '''R308K ARGINASE VARIANT...) |
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| - | [[Image:1hqx.gif|left|200px]]<br /><applet load="1hqx" size=" | + | [[Image:1hqx.gif|left|200px]]<br /><applet load="1hqx" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1hqx, resolution 3.Å" /> | caption="1hqx, resolution 3.Å" /> | ||
'''R308K ARGINASE VARIANT'''<br /> | '''R308K ARGINASE VARIANT'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The structure of the trimeric, manganese metalloenzyme, rat liver | + | The structure of the trimeric, manganese metalloenzyme, rat liver arginase, has been previously determined at 2.1-A resolution (Kanyo, Z. F., Scolnick, L. R., Ash, D. E., and Christianson, D. W., (1996) Nature 383, 554-557). A key feature of this structure is a novel S-shaped oligomerization motif at the carboxyl terminus of the protein that mediates approximately 54% of the intermonomer contacts. Arg-308, located within this oligomerization motif, nucleates a series of intramonomer and intermonomer salt links. In contrast to the trimeric wild-type enzyme, the R308A, R308E, and R308K variants of arginase exist as monomeric species, as determined by gel filtration and analytical ultracentrifugation, indicating that mutation of Arg-308 shifts the equilibrium for trimer dissociation by at least a factor of 10(5). These monomeric arginase variants are catalytically active, with k(cat)/K(m) values that are 13-17% of the value for wild-type enzyme. The arginase variants are characterized by decreased temperature stability relative to the wild-type enzyme. Differential scanning calorimetry shows that the midpoint temperature for unfolding of the Arg-308 variants is in the range of 63.6-65.5 degrees C, while the corresponding value for the wild-type enzyme is 70 degrees C. The three-dimensional structure of the R308K variant has been determined at 3-A resolution. At the high protein concentrations utilized in the crystallizations, this variant exists as a trimer, but weakened salt link interactions are observed for Lys-308. |
==About this Structure== | ==About this Structure== | ||
| - | 1HQX is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Rattus_norvegicus Rattus norvegicus] with MN as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Arginase Arginase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.5.3.1 3.5.3.1] Full crystallographic information is available from [http:// | + | 1HQX is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Rattus_norvegicus Rattus norvegicus] with <scene name='pdbligand=MN:'>MN</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Arginase Arginase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.5.3.1 3.5.3.1] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1HQX OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Rattus norvegicus]] | [[Category: Rattus norvegicus]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Ash, D | + | [[Category: Ash, D E.]] |
| - | [[Category: Brigham-Burke, M | + | [[Category: Brigham-Burke, M R.]] |
| - | [[Category: Christianson, D | + | [[Category: Christianson, D W.]] |
| - | [[Category: Cox, J | + | [[Category: Cox, J D.]] |
| - | [[Category: Doyle, M | + | [[Category: Doyle, M L.]] |
| - | [[Category: Jr., T | + | [[Category: Jr., T M.Sossong.]] |
| - | [[Category: Lavulo, L | + | [[Category: Lavulo, L T.]] |
[[Category: MN]] | [[Category: MN]] | ||
[[Category: arginase]] | [[Category: arginase]] | ||
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[[Category: subunit-subunit interactions]] | [[Category: subunit-subunit interactions]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:04:01 2008'' |
Revision as of 11:04, 21 February 2008
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R308K ARGINASE VARIANT
Overview
The structure of the trimeric, manganese metalloenzyme, rat liver arginase, has been previously determined at 2.1-A resolution (Kanyo, Z. F., Scolnick, L. R., Ash, D. E., and Christianson, D. W., (1996) Nature 383, 554-557). A key feature of this structure is a novel S-shaped oligomerization motif at the carboxyl terminus of the protein that mediates approximately 54% of the intermonomer contacts. Arg-308, located within this oligomerization motif, nucleates a series of intramonomer and intermonomer salt links. In contrast to the trimeric wild-type enzyme, the R308A, R308E, and R308K variants of arginase exist as monomeric species, as determined by gel filtration and analytical ultracentrifugation, indicating that mutation of Arg-308 shifts the equilibrium for trimer dissociation by at least a factor of 10(5). These monomeric arginase variants are catalytically active, with k(cat)/K(m) values that are 13-17% of the value for wild-type enzyme. The arginase variants are characterized by decreased temperature stability relative to the wild-type enzyme. Differential scanning calorimetry shows that the midpoint temperature for unfolding of the Arg-308 variants is in the range of 63.6-65.5 degrees C, while the corresponding value for the wild-type enzyme is 70 degrees C. The three-dimensional structure of the R308K variant has been determined at 3-A resolution. At the high protein concentrations utilized in the crystallizations, this variant exists as a trimer, but weakened salt link interactions are observed for Lys-308.
About this Structure
1HQX is a Single protein structure of sequence from Rattus norvegicus with as ligand. Active as Arginase, with EC number 3.5.3.1 Full crystallographic information is available from OCA.
Reference
Subunit-subunit interactions in trimeric arginase. Generation of active monomers by mutation of a single amino acid., Lavulo LT, Sossong TM Jr, Brigham-Burke MR, Doyle ML, Cox JD, Christianson DW, Ash DE, J Biol Chem. 2001 Apr 27;276(17):14242-8. Epub 2001 Jan 24. PMID:11278703
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