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- | [[Image:1hqx.gif|left|200px]] | + | {{Seed}} |
| + | [[Image:1hqx.png|left|200px]] |
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| {{STRUCTURE_1hqx| PDB=1hqx | SCENE= }} | | {{STRUCTURE_1hqx| PDB=1hqx | SCENE= }} |
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- | '''R308K ARGINASE VARIANT'''
| + | ===R308K ARGINASE VARIANT=== |
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- | ==Overview==
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- | 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. | + | The line below this paragraph, {{ABSTRACT_PUBMED_11278703}}, adds the Publication Abstract to the page |
| + | (as it appears on PubMed at http://www.pubmed.gov), where 11278703 is the PubMed ID number. |
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| + | {{ABSTRACT_PUBMED_11278703}} |
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| ==About this Structure== | | ==About this Structure== |
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| [[Category: Mutagenesis]] | | [[Category: Mutagenesis]] |
| [[Category: Subunit-subunit interaction]] | | [[Category: Subunit-subunit interaction]] |
- | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 19:08:35 2008'' | + | |
| + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 1 08:33:50 2008'' |
Revision as of 05:33, 1 July 2008
Template:STRUCTURE 1hqx
R308K ARGINASE VARIANT
Template:ABSTRACT PUBMED 11278703
About this Structure
1HQX is a Single protein structure of sequence from Rattus norvegicus. 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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