[93] 2-Keto-3-deoxy-d-glucarate aldolase

Fish, Donald C.; Blumenthal, Harold J.

doi:10.1016/0076-6879(66)09105-5

Cited by 25 publications

(11 citation statements)

References 3 publications

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“…4.1.3) are Class II (metal ion dependent) pyruvate-specific aldolases of identical sequences involved in the last step of 3-and 4-hydroxyphenylacetate catabolism in Escherichia coli strain W and C, respectively [2]. They are homologous to 2-dehydro-3-deoxygalactarate (DDG) aldolase [3] and an aldolase involved in the degradation of the aromatic pollutant, tetralin [4]. These enzymes utilize 4-substituted derivatives of 4-hydroxy-2-ketobutanoate as substrates, with an (S) configuration at carbon 4 [3,5].…”

Section: Introductionmentioning

confidence: 99%

“…They are homologous to 2-dehydro-3-deoxygalactarate (DDG) aldolase [3] and an aldolase involved in the degradation of the aromatic pollutant, tetralin [4]. These enzymes utilize 4-substituted derivatives of 4-hydroxy-2-ketobutanoate as substrates, with an (S) configuration at carbon 4 [3,5]. Indeed, HpaI was found to have broad substrate specificity, catalyzing the aldol cleavage of 4-hydroxy-2-ketopentanoate (HOPA), 4-hydroxy-2-ketohexanoate and KDO, yielding pyruvate and an aldehyde [2].…”

Section: Introductionmentioning

confidence: 99%

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The role of a conserved histidine residue in a pyruvate‐specific Class II aldolase

Wang

Seah

2008

FEBS Letters

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Histidine 45 in HpaI was replaced with alanine (H45A) and glutamine (H45Q). In the aldol cleavage reaction, k cat values were lowered by 78-and 2059-fold while K m values were increased by 100-and 42-fold in H45A and H45Q, respectively, compared to the wild-type enzyme. Both mutants displayed higher dissociation constants towards the metal cofactor, pyruvate and the transition state analogue, oxalate. Pyruvate proton exchange rates are consequently reduced in H45A and H45Q. pK a for a catalytic base (6.5) is lost in the mutant enzymes and catalysis is dependent on hydroxide ions. The results show that histidine 45 is important for metal cofactor binding and for facilitating C4-OH proton abstraction of the substrate in the reaction mechanism. Crown

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The role of a conserved histidine residue in a pyruvate‐specific Class II aldolase

Wang

Seah

2008

FEBS Letters

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“…The enzyme is part of the catabolic pathway for D ‐glucarate/galactarate utilization in Escherichia coli (Hubbard et al ., 1998). DDG aldolase has a considerable advantage with respect to other aldolases due to its low substrate specificity and its ability to condense a wide range of aldehydes with pyruvic acid (Fish and Blumenthal, 1966). Elucidation of the reaction mechanism of DDG aldolase may pave the way to progress in rational protein engineering towards altered substrate specificity and generation of new catalysts for synthetic chemistry.…”

Section: Introductionmentioning

confidence: 99%

“…Components are depicted in the Fisher projection. The equilibrium constant lies far in the direction of cleavage (Fish and Blumenthal, 1966).…”

Section: Introductionmentioning

confidence: 99%

Crystal structures of the metal-dependent 2-dehydro-3-deoxy-galactarate aldolase suggest a novel reaction mechanism

Izard

Blackwell

2000

The EMBO Journal

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Carbon-carbon bond formation is an essential reaction in organic chemistry and the use of aldolase enzymes for the stereochemical control of such reactions is an attractive alternative to conventional chemical methods. Here we describe the crystal structures of a novel class II enzyme, 2-dehydro-3-deoxy-galactarate (DDG) aldolase from Escherichia coli, in the presence and absence of substrate. The crystal structure was determined by locating only four Se sites to obtain phases for 506 protein residues. The protomer displays a modified (alpha/beta)(8) barrel fold, in which the eighth alpha-helix points away from the beta-barrel instead of packing against it. Analysis of the DDG aldolase crystal structures suggests a novel aldolase mechanism in which a phosphate anion accepts the proton from the methyl group of pyruvate.

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“…Thus, SbnG was suggested to have metaldependent aldolase activity and to possibly participate in SB degradation for iron release (17). Furthermore, a homolog found in the biosynthetic operon for the siderophore achromobactin, AcsB, was speculated to play a role in converting an intermediate into pyruvate and an aldehyde, which would eventually feed into siderophore biosynthesis (49 (41,51). To the best of our knowledge, no example exists in the literature where Ca 2ϩ serves as a functional cofactor in class II aldolases.…”

Section: Discussionmentioning

confidence: 99%