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Literature summary extracted from

  • Kallio, P.; Sultana, A.; Niemi, J.; Maentsaelae, P.; Schneider, G.
    Crystal structure of the polyketide cyclase AknH with bound substrate and product analogue: implications for catalytic mechanism and product stereoselectivity (2006), J. Mol. Biol., 357, 210-220.
    View publication on PubMed

Cloned(Commentary)

EC Number Cloned (Comment) Organism
5.5.1.B6 expression in Escherichia coli Streptomyces galilaeus

Crystallization (Commentary)

EC Number Crystallization (Comment) Organism
5.5.1.B6 AknH forms a tetramer of 222 symmetry. Two subunits (A-B and C-D, respectively), related by one of the 2-fold symmetry axes, form tight dimer interfaces. The side-chains of Thr128, Gln105 and the main-chain nitrogen of Val92 each interact with oxygen atoms of the polyketide core of the product via a water molecule. Additional enzyme-ligand interactions involve residues Arg120 and Trp122 from the other monomer across the subunit-subunit interface Streptomyces galilaeus

Protein Variants

EC Number Protein Variants Comment Organism
5.5.1.B6 D121A 0.2% of wild-type activity, (R)-configuration at C9 of product Streptomyces galilaeus
5.5.1.B6 H107A 2% of wild-type activity, (R)-configuration at C9 of product Streptomyces galilaeus
5.5.1.B6 N51L exchange to corresponding residues of SnoaL, EC 5.5.1.26, producing product with (S)-configuration. 20% of wild-type activity, about 50% (S)-configuration at C9 of product Streptomyces galilaeus
5.5.1.B6 Q105A 6% of wild-type activity, (R)-configuration at C9 of product Streptomyces galilaeus
5.5.1.B6 Y15F exchange to corresponding residues of SnoaL, EC 5.5.1.26, producing product with (S)-configuration. 45% of wild-type activity, about 20% (S)-configuration at C9 of product Streptomyces galilaeus

KM Value [mM]

EC Number KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
5.5.1.B6 0.002
-
 nogalonic acid methyl ester pH 7.4, temperature not specified in the publication Streptomyces galilaeus

Natural Substrates/ Products (Substrates)

EC Number Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
5.5.1.B6 aklanonic acid methyl ester Streptomyces galilaeus
-
 ?
-
 ?
5.5.1.B6 nogalonic acid methyl ester Streptomyces galilaeus
-
 auraviketone product has (R)-configuration at C9, ring closure is an intramolecular aldol condensation. The attack of the enol(ate) is on the si face of the C9 carbonyl group, required for the formation of the C9-R stereoisomer, which results in the alcoholate anion pointing away from the carboxyl side-chain of Asp121 ?

Organism

EC Number Organism UniProt Comment Textmining
5.5.1.B6 Streptomyces galilaeus O52646
-
-

Substrates and Products (Substrate)

EC Number Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
5.5.1.B6 aklanonic acid methyl ester
-
 Streptomyces galilaeus ?
-
 ?
5.5.1.B6 nogalonic acid methyl ester
-
 Streptomyces galilaeus auraviketone product has (R)-configuration at C9, ring closure is an intramolecular aldol condensation. The attack of the enol(ate) is on the si face of the C9 carbonyl group, required for the formation of the C9-R stereoisomer, which results in the alcoholate anion pointing away from the carboxyl side-chain of Asp121 ?

Synonyms

EC Number Synonyms Comment Organism
5.5.1.B6 AcmA
-
 Streptomyces galilaeus
5.5.1.B6 aklanonic acid methyl ester cyclase
-
 Streptomyces galilaeus
5.5.1.B6 AknH
-
 Streptomyces galilaeus

Turnover Number [1/s]

EC Number Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
5.5.1.B6 1
-
 nogalonic acid methyl ester pH 7.4, temperature not specified in the publication Streptomyces galilaeus

pH Optimum

EC Number pH Optimum Minimum pH Optimum Maximum Comment Organism
5.5.1.B6 7.2
-
-
 Streptomyces galilaeus