Identification of the missing links in prokaryotic pentose oxidation pathways : evidence for enzyme recruitment

• The pentose metabolism of Archaea is largely unknown. Here, we have employed an integrated genomics approach including DNA microarray and proteomics analyses to elucidate the catabolic pathway for D-arabinose in Sulfolobus solfataricus. During growth on this sugar, a small set of genes appeared to be differentially expressed compared with growth on D-glucose. These genes were heterologously overexpressed in Escherichia coli, and the recombinant proteins were purified and biochemically studied. This showed that D-arabinose is oxidized to 2-oxoglutarate by the consecutive action of a number of previously uncharacterized enzymes, including a D-arabinose dehydrogenase, a D-arabinonate dehydratase, a novel 2-keto-3-deoxy-D-arabinonate dehydratase, and a 2,5-dioxopentanoate dehydrogenase. Promoter analysis of these genes revealed a palindromic sequence upstream of the TATA box, which is likely to be involved in their concerted transcriptional control. Integration of the obtained biochemical data with genomic context analysis strongly suggests the occurrence of pentose oxidation pathways in both Archaea and Bacteria, and predicts the involvement of additional enzyme components. Moreover, it revealed striking genetic similarities between the catabolic pathways for pentoses, hexaric acids, and hydroxyproline degradation, which support the theory of metabolic pathway genesis by enzyme recruitment.

Ämnesord

NATURVETENSKAP  -- Biologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences (hsv//eng)

NATURVETENSKAP  -- Biologi -- Biokemi och molekylärbiologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Biochemistry and Molecular Biology (hsv//eng)

Nyckelord

Arabinose/chemistry

Base Sequence

Computational Biology/methods

Escherichia coli/metabolism

Glucose/metabolism

Ketoglutaric Acids/chemistry

Models; Biological

Models; Chemical

Molecular Sequence Data

Pentoses/chemistry

Proteomics/methods

Pyruvic Acid/chemistry

Recombinant Proteins/chemistry

Sulfolobus solfataricus/*enzymology/metabolism

Biology

Biologi

Publikations- och innehållstyp

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