1bq1
From Proteopedia
(New page: 200px<br /><applet load="1bq1" size="450" color="white" frame="true" align="right" spinBox="true" caption="1bq1, resolution 2.5Å" /> '''E. COLI THYMIDYLATE S...) |
|||
| Line 1: | Line 1: | ||
| - | [[Image:1bq1.gif|left|200px]]<br /><applet load="1bq1" size=" | + | [[Image:1bq1.gif|left|200px]]<br /><applet load="1bq1" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1bq1, resolution 2.5Å" /> | caption="1bq1, resolution 2.5Å" /> | ||
'''E. COLI THYMIDYLATE SYNTHASE MUTANT N177A IN COMPLEX WITH CB3717 AND 2'-DEOXYURIDINE 5'-MONOPHOSPHATE (DUMP)'''<br /> | '''E. COLI THYMIDYLATE SYNTHASE MUTANT N177A IN COMPLEX WITH CB3717 AND 2'-DEOXYURIDINE 5'-MONOPHOSPHATE (DUMP)'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Mutation of thymidylate synthase N229(177) to alanine results in an | + | Mutation of thymidylate synthase N229(177) to alanine results in an essentially inactive enzyme, yet it leads to formation of a stable ternary complex. The kinetics of N229(177)A show that kcat for Escherichia coli is reduced by 200-fold while the Km for dUMP is increased 200-fold and the Km for folate increased by tenfold versus the wild-type enzyme. The crystal structures of N229(177)A in complex with dUMP and CB3717, and in complex with dUMP alone are determined at 2.4 A, and 2.5 A resolution. These structures identify the covalently bound ternary complex and show how N229(177)A traps an intermediate, and so becomes inactive in a later step of the reaction. Since the smaller alanine side-chain at N229(177)A does not directly sterically impair binding of ligands, the structures implicate, and place quantitative limits on the involvement of the structured water network in the active site of thymidylate synthase in both catalysis and in determining the binding affinity for dUMP (in contrast, the N229(177)V mutation in Lactobacillus casei has minimal effect on activity). |
==About this Structure== | ==About this Structure== | ||
| - | 1BQ1 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 UMP and CB3 as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Thymidylate_synthase Thymidylate synthase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.1.1.45 2.1.1.45] Full crystallographic information is available from [http:// | + | 1BQ1 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=UMP:'>UMP</scene> and <scene name='pdbligand=CB3:'>CB3</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Thymidylate_synthase Thymidylate synthase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.1.1.45 2.1.1.45] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1BQ1 OCA]. |
==Reference== | ==Reference== | ||
| Line 14: | Line 14: | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Thymidylate synthase]] | [[Category: Thymidylate synthase]] | ||
| - | [[Category: Finer-Moore, J | + | [[Category: Finer-Moore, J S.]] |
| - | [[Category: Reyes, C | + | [[Category: Reyes, C L.]] |
| - | [[Category: Rutenber, E | + | [[Category: Rutenber, E E.]] |
| - | [[Category: Sage, C | + | [[Category: Sage, C R.]] |
| - | [[Category: Stroud, R | + | [[Category: Stroud, R M.]] |
[[Category: CB3]] | [[Category: CB3]] | ||
[[Category: UMP]] | [[Category: UMP]] | ||
| Line 25: | Line 25: | ||
[[Category: transferase]] | [[Category: transferase]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 11:57:54 2008'' |
Revision as of 09:58, 21 February 2008
|
E. COLI THYMIDYLATE SYNTHASE MUTANT N177A IN COMPLEX WITH CB3717 AND 2'-DEOXYURIDINE 5'-MONOPHOSPHATE (DUMP)
Overview
Mutation of thymidylate synthase N229(177) to alanine results in an essentially inactive enzyme, yet it leads to formation of a stable ternary complex. The kinetics of N229(177)A show that kcat for Escherichia coli is reduced by 200-fold while the Km for dUMP is increased 200-fold and the Km for folate increased by tenfold versus the wild-type enzyme. The crystal structures of N229(177)A in complex with dUMP and CB3717, and in complex with dUMP alone are determined at 2.4 A, and 2.5 A resolution. These structures identify the covalently bound ternary complex and show how N229(177)A traps an intermediate, and so becomes inactive in a later step of the reaction. Since the smaller alanine side-chain at N229(177)A does not directly sterically impair binding of ligands, the structures implicate, and place quantitative limits on the involvement of the structured water network in the active site of thymidylate synthase in both catalysis and in determining the binding affinity for dUMP (in contrast, the N229(177)V mutation in Lactobacillus casei has minimal effect on activity).
About this Structure
1BQ1 is a Single protein structure of sequence from Escherichia coli with and as ligands. Active as Thymidylate synthase, with EC number 2.1.1.45 Full crystallographic information is available from OCA.
Reference
Inactivity of N229A thymidylate synthase due to water-mediated effects: isolating a late stage in methyl transfer., Reyes CL, Sage CR, Rutenber EE, Nissen RM, Finer-Moore JS, Stroud RM, J Mol Biol. 1998 Dec 4;284(3):699-712. PMID:9826509
Page seeded by OCA on Thu Feb 21 11:57:54 2008
