1tmh: Difference between revisions
New page: left|200px<br /><applet load="1tmh" size="450" color="white" frame="true" align="right" spinBox="true" caption="1tmh, resolution 2.8Å" /> '''MODULAR MUTAGENESIS O... |
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[[Image:1tmh.gif|left|200px]]<br /><applet load="1tmh" size=" | [[Image:1tmh.gif|left|200px]]<br /><applet load="1tmh" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1tmh, resolution 2.8Å" /> | caption="1tmh, resolution 2.8Å" /> | ||
'''MODULAR MUTAGENESIS OF A TIM-BARREL ENZYME: THE CRYSTAL STRUCTURE OF A CHIMERIC E. COLI TIM HAVING THE EIGHTH (BETA-ALPHA)-UNIT REPLACED BY THE EQUIVALENT UNIT OF CHICKEN TIM'''<br /> | '''MODULAR MUTAGENESIS OF A TIM-BARREL ENZYME: THE CRYSTAL STRUCTURE OF A CHIMERIC E. COLI TIM HAVING THE EIGHTH (BETA-ALPHA)-UNIT REPLACED BY THE EQUIVALENT UNIT OF CHICKEN TIM'''<br /> | ||
==Overview== | ==Overview== | ||
The crystal structure of a hybrid Escherichia coli triosephosphate | The crystal structure of a hybrid Escherichia coli triosephosphate isomerase (TIM) has been determined at 2.8 A resolution. The hybrid TIM (ETIM8CHI) was constructed by replacing the eighth beta alpha-unit of E. coli TIM with the equivalent unit of chicken TIM. This replacement involves 10 sequence changes. One of the changes concerns the mutation of a buried alanine (Ala232 in strand 8) into a phenylalanine. The ETIM8CHI structure shows that the A232F sequence change can be incorporated by a side-chain rotation of Phe224 (in helix 7). No cavities or strained dihedrals are observed in ETIM8CHI in the region near position 232, which is in agreement with the observation that ETIM8CHI and E.coli TIM have similar stabilities. The largest CA (C-alpha atom) movements, approximately 3 A, are seen for the C-terminal end of helix 8 (associated with the outward rotation of Phe224) and for the residues in the loop after helix 1 (associated with sequence changes in helix 8). From the structure it is not clear why the kcat of ETIM8CHI is 10 times lower than in wild type E.coli TIM. | ||
==About this Structure== | ==About this Structure== | ||
1TMH is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with SO4 as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Triose-phosphate_isomerase Triose-phosphate isomerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=5.3.1.1 5.3.1.1] Full crystallographic information is available from [http:// | 1TMH is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with <scene name='pdbligand=SO4:'>SO4</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Triose-phosphate_isomerase Triose-phosphate isomerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=5.3.1.1 5.3.1.1] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1TMH OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Triose-phosphate isomerase]] | [[Category: Triose-phosphate isomerase]] | ||
[[Category: Kishan, K | [[Category: Kishan, K V.Radha.]] | ||
[[Category: Wierenga, R | [[Category: Wierenga, R K.]] | ||
[[Category: Zeelen, J | [[Category: Zeelen, J Ph.]] | ||
[[Category: SO4]] | [[Category: SO4]] | ||
[[Category: isomerase(intramolecular oxidoreductase)]] | [[Category: isomerase(intramolecular oxidoreductase)]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:15:12 2008'' | ||
Revision as of 16:15, 21 February 2008
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MODULAR MUTAGENESIS OF A TIM-BARREL ENZYME: THE CRYSTAL STRUCTURE OF A CHIMERIC E. COLI TIM HAVING THE EIGHTH (BETA-ALPHA)-UNIT REPLACED BY THE EQUIVALENT UNIT OF CHICKEN TIM
OverviewOverview
The crystal structure of a hybrid Escherichia coli triosephosphate isomerase (TIM) has been determined at 2.8 A resolution. The hybrid TIM (ETIM8CHI) was constructed by replacing the eighth beta alpha-unit of E. coli TIM with the equivalent unit of chicken TIM. This replacement involves 10 sequence changes. One of the changes concerns the mutation of a buried alanine (Ala232 in strand 8) into a phenylalanine. The ETIM8CHI structure shows that the A232F sequence change can be incorporated by a side-chain rotation of Phe224 (in helix 7). No cavities or strained dihedrals are observed in ETIM8CHI in the region near position 232, which is in agreement with the observation that ETIM8CHI and E.coli TIM have similar stabilities. The largest CA (C-alpha atom) movements, approximately 3 A, are seen for the C-terminal end of helix 8 (associated with the outward rotation of Phe224) and for the residues in the loop after helix 1 (associated with sequence changes in helix 8). From the structure it is not clear why the kcat of ETIM8CHI is 10 times lower than in wild type E.coli TIM.
About this StructureAbout this Structure
1TMH is a Single protein structure of sequence from Escherichia coli with as ligand. Active as Triose-phosphate isomerase, with EC number 5.3.1.1 Full crystallographic information is available from OCA.
ReferenceReference
Modular mutagenesis of a TIM-barrel enzyme: the crystal structure of a chimeric E. coli TIM having the eighth beta alpha-unit replaced by the equivalent unit of chicken TIM., Kishan R, Zeelen JP, Noble ME, Borchert TV, Mainfroid V, Goraj K, Martial JA, Wierenga RK, Protein Eng. 1994 Aug;7(8):945-51. PMID:7809033
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