1hjf
From Proteopedia
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==Overview== | ==Overview== | ||
| - | Deacetoxycephalosporin C synthase is an iron(II) 2-oxoglutaratedependent | + | Deacetoxycephalosporin C synthase is an iron(II) 2-oxoglutaratedependent oxygenase that catalyzes the oxidative ring-expansion of penicillin N to deacetoxycephalosporin C. The wild-type enzyme is only able to efficiently utilize 2-oxoglutarate and 2-oxoadipate as a 2-oxoacid co-substrate. Mutation of arginine 258, the side chain of which forms an electrostatic interaction with the 5-carboxylate of the 2-oxoglutarate co-substrate, to a glutamine residue reduced activity to about 5% of the wild-type enzyme with 2-oxoglutarate. However, other aliphatic 2-oxoacids, which were not co-substrates for the wild-type enzyme, were utilized by the R258Q mutant. These 2-oxoacids "rescued" catalytic activity to the level observed for the wild-type enzyme as judged by penicillin N and G conversion. These co-substrates underwent oxidative decarboxylation as observed for 2-oxoglutarate in the normal reaction with the wild-type enzyme. Crystal structures of the iron(II)- 2-oxo-3-methylbutanoate (1.5 A), and iron(II)-2-oxo-4-methylpentanoate (1.6 A) enzyme complexes were obtained, which reveal the molecular basis for this "chemical co-substrate rescue" and help to rationalize the co-substrate selectivity of 2-oxoglutaratedependent oxygenases. |
==About this Structure== | ==About this Structure== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Streptomyces clavuligerus]] | [[Category: Streptomyces clavuligerus]] | ||
| - | [[Category: Baldwin, J | + | [[Category: Baldwin, J E.]] |
| - | [[Category: Clifton, I | + | [[Category: Clifton, I J.]] |
[[Category: Dubus, A.]] | [[Category: Dubus, A.]] | ||
| - | [[Category: Frere, J | + | [[Category: Frere, J M.]] |
[[Category: Harlos, K.]] | [[Category: Harlos, K.]] | ||
| - | [[Category: Lee, H | + | [[Category: Lee, H J.]] |
| - | [[Category: Lloyd, M | + | [[Category: Lloyd, M D.]] |
| - | [[Category: Schofield, C | + | [[Category: Schofield, C J.]] |
[[Category: COI]] | [[Category: COI]] | ||
[[Category: FE2]] | [[Category: FE2]] | ||
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[[Category: co-substrate selectivity]] | [[Category: co-substrate selectivity]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:01:55 2008'' |
Revision as of 11:01, 21 February 2008
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ALTERATION OF THE CO-SUBSTRATE SELECTIVITY OF DEACETOXYCEPHALOSPORIN C SYNTHASE: THE ROLE OF ARGININE-258
Overview
Deacetoxycephalosporin C synthase is an iron(II) 2-oxoglutaratedependent oxygenase that catalyzes the oxidative ring-expansion of penicillin N to deacetoxycephalosporin C. The wild-type enzyme is only able to efficiently utilize 2-oxoglutarate and 2-oxoadipate as a 2-oxoacid co-substrate. Mutation of arginine 258, the side chain of which forms an electrostatic interaction with the 5-carboxylate of the 2-oxoglutarate co-substrate, to a glutamine residue reduced activity to about 5% of the wild-type enzyme with 2-oxoglutarate. However, other aliphatic 2-oxoacids, which were not co-substrates for the wild-type enzyme, were utilized by the R258Q mutant. These 2-oxoacids "rescued" catalytic activity to the level observed for the wild-type enzyme as judged by penicillin N and G conversion. These co-substrates underwent oxidative decarboxylation as observed for 2-oxoglutarate in the normal reaction with the wild-type enzyme. Crystal structures of the iron(II)- 2-oxo-3-methylbutanoate (1.5 A), and iron(II)-2-oxo-4-methylpentanoate (1.6 A) enzyme complexes were obtained, which reveal the molecular basis for this "chemical co-substrate rescue" and help to rationalize the co-substrate selectivity of 2-oxoglutaratedependent oxygenases.
About this Structure
1HJF is a Single protein structure of sequence from Streptomyces clavuligerus with and as ligands. Known structural/functional Sites: and . Full crystallographic information is available from OCA.
Reference
Alteration of the co-substrate selectivity of deacetoxycephalosporin C synthase. The role of arginine 258., Lee HJ, Lloyd MD, Clifton IJ, Harlos K, Dubus A, Baldwin JE, Frere JM, Schofield CJ, J Biol Chem. 2001 May 25;276(21):18290-5. Epub 2001 Feb 21. PMID:11279000
Page seeded by OCA on Thu Feb 21 13:01:55 2008
Categories: Single protein | Streptomyces clavuligerus | Baldwin, J E. | Clifton, I J. | Dubus, A. | Frere, J M. | Harlos, K. | Lee, H J. | Lloyd, M D. | Schofield, C J. | COI | FE2 | 2-oxoglutarate-dependent oxygenase | Alternative 2-oxoacids | Cephem antibiotic biosynthesis | Chemical cosubstrate rescue | Co-substrate selectivity
