9aat
From Proteopedia
(New page: 200px<br /><applet load="9aat" size="450" color="white" frame="true" align="right" spinBox="true" caption="9aat, resolution 2.2Å" /> '''X-RAY STRUCTURE REFIN...) |
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| - | [[Image:9aat.jpg|left|200px]]<br /><applet load="9aat" size=" | + | [[Image:9aat.jpg|left|200px]]<br /><applet load="9aat" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="9aat, resolution 2.2Å" /> | caption="9aat, resolution 2.2Å" /> | ||
'''X-RAY STRUCTURE REFINEMENT AND COMPARISON OF THREE FORMS OF MITOCHONDRIAL ASPARTATE AMINOTRANSFERASE'''<br /> | '''X-RAY STRUCTURE REFINEMENT AND COMPARISON OF THREE FORMS OF MITOCHONDRIAL ASPARTATE AMINOTRANSFERASE'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The X-ray crystal structures of three forms of the enzyme aspartate | + | The X-ray crystal structures of three forms of the enzyme aspartate aminotransferase (EC 2.6.1.1) from chicken heart mitochondria have been refined by least-squares methods: holoenzyme with the co-factor pyridoxal-5'-phosphate bound at pH 7.5 (1.9 A resolution), holoenzyme with pyridoxal-5'-phosphate bound at pH 5.1 (2.3 A resolution) and holoenzyme with the co-factor pyridoxamine-5'-phosphate bound at pH 7.5 (2.2 A resolution). The crystallographic agreement factors [formula: see text] for the structures are 0.166, 0.130 and 0.131, respectively, for all data in the resolution range from 10.0 A to the limit of diffraction for each structure. The secondary, super-secondary and domain structures of the pyridoxal-phosphate holoenzyme at pH 7.5 are described in detail. The surface area of the interface between the monomer subunits of this dimeric alpha 2 protein is unusually large, indicating a very stable dimer. This is consistent with biochemical data. Both subunit and domain interfaces are relatively smooth compared with other proteins. The interactions of the protein with its co-factor are described and compared among the three structures. Observed changes in co-factor conformation may be related to spectral changes and the energetics of the catalytic reaction. Small but significant adjustments of the protein to changes in co-factor conformation are seen. These adjustments may be accommodated by small rigid-body shifts of secondary structural elements, and by packing defects in the protein core. |
==About this Structure== | ==About this Structure== | ||
| - | 9AAT is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Gallus_gallus Gallus gallus] with PMP as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Aspartate_transaminase Aspartate transaminase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.6.1.1 2.6.1.1] Full crystallographic information is available from [http:// | + | 9AAT is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Gallus_gallus Gallus gallus] with <scene name='pdbligand=PMP:'>PMP</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Aspartate_transaminase Aspartate transaminase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.6.1.1 2.6.1.1] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=9AAT OCA]. |
==Reference== | ==Reference== | ||
| Line 14: | Line 14: | ||
[[Category: Gallus gallus]] | [[Category: Gallus gallus]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Jansonius, J | + | [[Category: Jansonius, J N.]] |
| - | [[Category: Mcphalen, C | + | [[Category: Mcphalen, C A.]] |
| - | [[Category: Vincent, M | + | [[Category: Vincent, M G.]] |
[[Category: PMP]] | [[Category: PMP]] | ||
[[Category: transferase(aminotransferase)]] | [[Category: transferase(aminotransferase)]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 19:18:22 2008'' |
Revision as of 17:18, 21 February 2008
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X-RAY STRUCTURE REFINEMENT AND COMPARISON OF THREE FORMS OF MITOCHONDRIAL ASPARTATE AMINOTRANSFERASE
Overview
The X-ray crystal structures of three forms of the enzyme aspartate aminotransferase (EC 2.6.1.1) from chicken heart mitochondria have been refined by least-squares methods: holoenzyme with the co-factor pyridoxal-5'-phosphate bound at pH 7.5 (1.9 A resolution), holoenzyme with pyridoxal-5'-phosphate bound at pH 5.1 (2.3 A resolution) and holoenzyme with the co-factor pyridoxamine-5'-phosphate bound at pH 7.5 (2.2 A resolution). The crystallographic agreement factors [formula: see text] for the structures are 0.166, 0.130 and 0.131, respectively, for all data in the resolution range from 10.0 A to the limit of diffraction for each structure. The secondary, super-secondary and domain structures of the pyridoxal-phosphate holoenzyme at pH 7.5 are described in detail. The surface area of the interface between the monomer subunits of this dimeric alpha 2 protein is unusually large, indicating a very stable dimer. This is consistent with biochemical data. Both subunit and domain interfaces are relatively smooth compared with other proteins. The interactions of the protein with its co-factor are described and compared among the three structures. Observed changes in co-factor conformation may be related to spectral changes and the energetics of the catalytic reaction. Small but significant adjustments of the protein to changes in co-factor conformation are seen. These adjustments may be accommodated by small rigid-body shifts of secondary structural elements, and by packing defects in the protein core.
About this Structure
9AAT is a Single protein structure of sequence from Gallus gallus with as ligand. Active as Aspartate transaminase, with EC number 2.6.1.1 Full crystallographic information is available from OCA.
Reference
X-ray structure refinement and comparison of three forms of mitochondrial aspartate aminotransferase., McPhalen CA, Vincent MG, Jansonius JN, J Mol Biol. 1992 May 20;225(2):495-517. PMID:1593633
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