1cg4: Difference between revisions
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[[Image:1cg4.jpg|left|200px]] | [[Image:1cg4.jpg|left|200px]] | ||
'''STRUCTURE OF THE MUTANT (R303L) OF ADENYLOSUCCINATE SYNTHETASE FROM E. COLI COMPLEXED WITH, GDP, 6-PHOSPHORYL-IMP, AND MG2+''' | {{Structure | ||
|PDB= 1cg4 |SIZE=350|CAPTION= <scene name='initialview01'>1cg4</scene>, resolution 2.5Å | |||
|SITE= | |||
|LIGAND= <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=IMO:6-O-PHOSPHORYL+INOSINE+MONOPHOSPHATE'>IMO</scene> and <scene name='pdbligand=GDP:GUANOSINE-5'-DIPHOSPHATE'>GDP</scene> | |||
|ACTIVITY= [http://en.wikipedia.org/wiki/Adenylosuccinate_synthase Adenylosuccinate synthase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=6.3.4.4 6.3.4.4] | |||
|GENE= | |||
}} | |||
'''STRUCTURE OF THE MUTANT (R303L) OF ADENYLOSUCCINATE SYNTHETASE FROM E. COLI COMPLEXED WITH, GDP, 6-PHOSPHORYL-IMP, AND MG2+''' | |||
==Overview== | ==Overview== | ||
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==About this Structure== | ==About this Structure== | ||
1CG4 is a [ | 1CG4 is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1CG4 OCA]. | ||
==Reference== | ==Reference== | ||
Mechanistic implications from crystalline complexes of wild-type and mutant adenylosuccinate synthetases from Escherichia coli., Choe JY, Poland BW, Fromm HJ, Honzatko RB, Biochemistry. 1999 May 25;38(21):6953-61. PMID:[http:// | Mechanistic implications from crystalline complexes of wild-type and mutant adenylosuccinate synthetases from Escherichia coli., Choe JY, Poland BW, Fromm HJ, Honzatko RB, Biochemistry. 1999 May 25;38(21):6953-61. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/10346917 10346917] | ||
[[Category: Adenylosuccinate synthase]] | [[Category: Adenylosuccinate synthase]] | ||
[[Category: Escherichia coli]] | [[Category: Escherichia coli]] | ||
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[[Category: MG]] | [[Category: MG]] | ||
[[Category: 6-phosporyl-imp]] | [[Category: 6-phosporyl-imp]] | ||
[[Category: gtp-hydrolysing | [[Category: gtp-hydrolysing enzyme]] | ||
[[Category: ligase]] | [[Category: ligase]] | ||
[[Category: purine 2 nucleotide biosynthesis]] | [[Category: purine 2 nucleotide biosynthesis]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Mar 20 10:24:04 2008'' | ||
Revision as of 11:24, 20 March 2008
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| , resolution 2.5Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | , and | ||||||
| Activity: | Adenylosuccinate synthase, with EC number 6.3.4.4 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
STRUCTURE OF THE MUTANT (R303L) OF ADENYLOSUCCINATE SYNTHETASE FROM E. COLI COMPLEXED WITH, GDP, 6-PHOSPHORYL-IMP, AND MG2+
OverviewOverview
Asp13 and His41 are essential residues of adenylosuccinate synthetase, putatively catalyzing the formation of adenylosuccinate from an intermediate of 6-phosphoryl-IMP. Wild-type adenylosuccinate synthetase and three mutant synthetases (Arg143 --> Leu, Lys16 --> Gln, and Arg303 --> Leu) from Eschericha coli have been crystallized in the presence of IMP, hadacidin (an analogue of L-aspartate), Mg2+, and GTP. The active site of each complex contains 6-phosphoryl-IMP, Mg2+, GDP, and hadacidin, except for the Arg303 --> Leu mutant, which does not bind hadacidin. In response to the formation of 6-phosphoryl-IMP, Asp13 enters the inner coordination sphere of the active site Mg2+. His41 hydrogen bonds with 6-phosphoryl-IMP, except in the Arg303 --> Leu complex, where it remains bound to the guanine nucleotide. Hence, recognition of the active site Mg2+ by Asp13 evidently occurs after the formation of 6-phosphoryl-IMP, but recognition of the intermediate by His41 may require the association of L-aspartate with the active site. Structures reported here support a mechanism in which Asp13 and His41 act as the catalytic base and acid, respectively, in the formation of 6-phosphoryl-IMP, and then act together as catalytic acids in the subsequent formation of adenylosuccinate.
About this StructureAbout this Structure
1CG4 is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
ReferenceReference
Mechanistic implications from crystalline complexes of wild-type and mutant adenylosuccinate synthetases from Escherichia coli., Choe JY, Poland BW, Fromm HJ, Honzatko RB, Biochemistry. 1999 May 25;38(21):6953-61. PMID:10346917
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