The missing link in the fungal D-galacturonate pathway

Identification of the L-threo-3-deoxy-hexulosonate aldolase

Satu Hilditch, Suvi Berghäll, Nisse Kalkkinen, Merja Penttilä, Peter Richard

Research output: Contribution to journalArticleScientificpeer-review

33 Citations (Scopus)

Abstract

The fungal path for the catabolism of D-galacturonate is only partially known. It is however distinctly different to the wellknown bacterial path. The known elements of the fungal path are D-galacturonate reductase converting D-galacturonate to L-galactonate and L-galactonate dehydratase converting L-galactonate to L-threo-3-deoxy-hexulosonate (2-keto-3-deoxy-L-galactonate). Here we describe the missing link in this pathway, an aldolase converting L-threo-3-deoxy-hexulosonate to pyruvate and L-glyceraldehyde. Fungal enzymes converting L-glyceraldehyde to glycerol have been described previously. The L-threo-3-deoxy-hexulosonate aldolase activity was induced in the mold Hypocrea jecorina (Trichoderma reesei) during growth on D-galacturonate. The enzyme was purified from this mold and a partial amino acid sequence obtained. This sequence was then used to identify the corresponding gene from the H. jecorina genome. The deletion of the gene resulted in a strain unable to grow on D-galacturonate and accumulating L-threo-3-deoxy-hexulosonate. The open reading frame was cloned from cDNA and functionally expressed in the yeast Saccharomyces cerevisiae. A histidine-tagged protein was expressed, purified, and characterized. The enzyme catalyzed reaction was reversible. With L-threo-3-deoxy-hexulosonate as substrate the Km was 3.5 mM and with pyruvate and L-glyceraldehyde the Km were 0.5 and 1.2 mM, respectively.

Original languageEnglish
Pages (from-to)26195-26201
Number of pages7
JournalJournal of Biological Chemistry
Volume282
Issue number36
DOIs
Publication statusPublished - 7 Sep 2007
MoE publication typeA1 Journal article-refereed

Fingerprint

Glyceraldehyde
Fructose-Bisphosphate Aldolase
galactonate dehydratase
Genes
Pyruvic Acid
Yeast
Hypocrea
Fungi
Enzymes
Trichoderma
Gene Deletion
Histidine
Glycerol
Open Reading Frames
Saccharomyces cerevisiae
Amino Acid Sequence
Complementary DNA
Yeasts
Genome
Amino Acids

Keywords

  • bacteria (microorganisms)
  • Hypocrea jecorina
  • Saccharomyces cerevisiae
  • Galacturonate reductases
  • Glyceraldehydes
  • Hexulosonate
  • Yeast
  • enzyme activity

Cite this

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title = "The missing link in the fungal D-galacturonate pathway: Identification of the L-threo-3-deoxy-hexulosonate aldolase",
abstract = "The fungal path for the catabolism of D-galacturonate is only partially known. It is however distinctly different to the wellknown bacterial path. The known elements of the fungal path are D-galacturonate reductase converting D-galacturonate to L-galactonate and L-galactonate dehydratase converting L-galactonate to L-threo-3-deoxy-hexulosonate (2-keto-3-deoxy-L-galactonate). Here we describe the missing link in this pathway, an aldolase converting L-threo-3-deoxy-hexulosonate to pyruvate and L-glyceraldehyde. Fungal enzymes converting L-glyceraldehyde to glycerol have been described previously. The L-threo-3-deoxy-hexulosonate aldolase activity was induced in the mold Hypocrea jecorina (Trichoderma reesei) during growth on D-galacturonate. The enzyme was purified from this mold and a partial amino acid sequence obtained. This sequence was then used to identify the corresponding gene from the H. jecorina genome. The deletion of the gene resulted in a strain unable to grow on D-galacturonate and accumulating L-threo-3-deoxy-hexulosonate. The open reading frame was cloned from cDNA and functionally expressed in the yeast Saccharomyces cerevisiae. A histidine-tagged protein was expressed, purified, and characterized. The enzyme catalyzed reaction was reversible. With L-threo-3-deoxy-hexulosonate as substrate the Km was 3.5 mM and with pyruvate and L-glyceraldehyde the Km were 0.5 and 1.2 mM, respectively.",
keywords = "bacteria (microorganisms), Hypocrea jecorina, Saccharomyces cerevisiae, Galacturonate reductases, Glyceraldehydes, Hexulosonate, Yeast, enzyme activity",
author = "Satu Hilditch and Suvi Bergh{\"a}ll and Nisse Kalkkinen and Merja Penttil{\"a} and Peter Richard",
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The missing link in the fungal D-galacturonate pathway : Identification of the L-threo-3-deoxy-hexulosonate aldolase. / Hilditch, Satu; Berghäll, Suvi; Kalkkinen, Nisse; Penttilä, Merja; Richard, Peter.

In: Journal of Biological Chemistry, Vol. 282, No. 36, 07.09.2007, p. 26195-26201.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - The missing link in the fungal D-galacturonate pathway

T2 - Identification of the L-threo-3-deoxy-hexulosonate aldolase

AU - Hilditch, Satu

AU - Berghäll, Suvi

AU - Kalkkinen, Nisse

AU - Penttilä, Merja

AU - Richard, Peter

N1 - CA2: TK402 ISI: BIOCHEMISTRY & MOLECULAR BIOLOGY

PY - 2007/9/7

Y1 - 2007/9/7

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KW - Galacturonate reductases

KW - Glyceraldehydes

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KW - Yeast

KW - enzyme activity

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