3aat
From Proteopedia
(New page: 200px<br /><applet load="3aat" size="450" color="white" frame="true" align="right" spinBox="true" caption="3aat, resolution 2.8Å" /> '''ACTIVITY AND STRUCTUR...) |
|||
| Line 1: | Line 1: | ||
| - | [[Image:3aat.gif|left|200px]]<br /><applet load="3aat" size=" | + | [[Image:3aat.gif|left|200px]]<br /><applet load="3aat" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="3aat, resolution 2.8Å" /> | caption="3aat, resolution 2.8Å" /> | ||
'''ACTIVITY AND STRUCTURE OF THE ACTIVE-SITE MUTANTS R386Y AND R386F OF ESCHERICHIA COLI ASPARTATE AMINOTRANSFERASE'''<br /> | '''ACTIVITY AND STRUCTURE OF THE ACTIVE-SITE MUTANTS R386Y AND R386F OF ESCHERICHIA COLI ASPARTATE AMINOTRANSFERASE'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Arginine-386, the active-site residue of Escherichia coli aspartate | + | Arginine-386, the active-site residue of Escherichia coli aspartate aminotransferase (EC 2.6.1.1) that binds the substrate alpha-carboxylate, was replaced with tyrosine and phenylalanine by site-directed mutagenesis. This experiment was undertaken to elucidate the roles of particular enzyme-substrate interactions in triggering the substrate-induced conformational change in the enzyme. The activity and crystal structure of the resulting mutants were examined. The apparent second-order rate constants of both of these mutants are reduced by more than 5 orders of magnitude as compared to that of wild-type enzyme, though R386Y is slightly more active than R386F. The 2.5-A resolution structure of R386F in its native state was determined by using difference Fourier methods. The overall structure is very similar to that of the wild-type enzyme in the open conformation. The position of the Phe-386 side chain, however, appears to shift with respect to that of Arg-386 in the wild-type enzyme and to form new contacts with neighboring residues. |
==About this Structure== | ==About this Structure== | ||
| - | 3AAT 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 and PLP as [http://en.wikipedia.org/wiki/ligands ligands]. 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:// | + | 3AAT 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> and <scene name='pdbligand=PLP:'>PLP</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. 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=3AAT OCA]. |
==Reference== | ==Reference== | ||
| Line 14: | Line 14: | ||
[[Category: Escherichia coli]] | [[Category: Escherichia coli]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Danishefsky, A | + | [[Category: Danishefsky, A T.]] |
| - | [[Category: Petsko, G | + | [[Category: Petsko, G A.]] |
[[Category: Ringe, D.]] | [[Category: Ringe, D.]] | ||
[[Category: PLP]] | [[Category: PLP]] | ||
| Line 21: | Line 21: | ||
[[Category: transferase(aminotransferase)]] | [[Category: transferase(aminotransferase)]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 19:02:41 2008'' |
Revision as of 17:02, 21 February 2008
|
ACTIVITY AND STRUCTURE OF THE ACTIVE-SITE MUTANTS R386Y AND R386F OF ESCHERICHIA COLI ASPARTATE AMINOTRANSFERASE
Overview
Arginine-386, the active-site residue of Escherichia coli aspartate aminotransferase (EC 2.6.1.1) that binds the substrate alpha-carboxylate, was replaced with tyrosine and phenylalanine by site-directed mutagenesis. This experiment was undertaken to elucidate the roles of particular enzyme-substrate interactions in triggering the substrate-induced conformational change in the enzyme. The activity and crystal structure of the resulting mutants were examined. The apparent second-order rate constants of both of these mutants are reduced by more than 5 orders of magnitude as compared to that of wild-type enzyme, though R386Y is slightly more active than R386F. The 2.5-A resolution structure of R386F in its native state was determined by using difference Fourier methods. The overall structure is very similar to that of the wild-type enzyme in the open conformation. The position of the Phe-386 side chain, however, appears to shift with respect to that of Arg-386 in the wild-type enzyme and to form new contacts with neighboring residues.
About this Structure
3AAT is a Single protein structure of sequence from Escherichia coli with and as ligands. Active as Aspartate transaminase, with EC number 2.6.1.1 Full crystallographic information is available from OCA.
Reference
Activity and structure of the active-site mutants R386Y and R386F of Escherichia coli aspartate aminotransferase., Danishefsky AT, Onnufer JJ, Petsko GA, Ringe D, Biochemistry. 1991 Feb 19;30(7):1980-5. PMID:1993208
Page seeded by OCA on Thu Feb 21 19:02:41 2008
