Journal article
Molecular Characterization of the α-Glucosidase Gene (malA) from the Hyperthermophilic Archaeon Sulfolobus solfataricus
Journal of bacteriology, Vol.180(5), pp.1287-1295
03/1998
Handle:
https://hdl.handle.net/2376/107318
PMCID: PMC107019
PMID: 9495770
Abstract
Acidic hot springs are colonized by a diversity of hyperthermophilic organisms requiring extremes of temperature and pH for growth. To clarify how carbohydrates are consumed in such locations, the structural gene (
malA
) encoding the major soluble α-glucosidase (maltase) and flanking sequences from
Sulfolobus solfataricus
were cloned and characterized. This is the first report of an α-glucosidase gene from the archaeal domain.
malA
is 2,083 bp and encodes a protein of 693 amino acids with a calculated mass of 80.5 kDa. It is flanked on the 5′ side by an unusual 1-kb intergenic region. Northern blot analysis of the
malA
region identified transcripts for
malA
and an upstream open reading frame located 5′ to the 1-kb intergenic region. The
malA
transcription start site was located by primer extension analysis to a guanine residue 8 bp 5′ of the
malA
start codon. Gel mobility shift analysis of the
malA
promoter region suggests that sequences 3′ to position −33, including a consensus archaeal TATA box, play an essential role in
malA
expression.
malA
homologs were detected by Southern blot analysis in other
S. solfataricus
strains and in
Sulfolobus shibatae
, while no homologs were evident in
Sulfolobus acidocaldarius
, lending further support to the proposed revision of the genus
Sulfolobus
. Phylogenetic analyses indicate that the closest
S. solfataricus
α-glucosidase homologs are of mammalian origin. Characterization of the recombinant enzyme purified from
Escherichia coli
revealed differences from the natural enzyme in thermostability and electrophoretic behavior. Glycogen is a substrate for the recombinant enzyme. Unlike maltose hydrolysis, glycogen hydrolysis is optimal at the intracellular pH of the organism. These results indicate a unique role for the
S. solfataricus
α-glucosidase in carbohydrate metabolism.
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Details
- Title
- Molecular Characterization of the α-Glucosidase Gene (malA) from the Hyperthermophilic Archaeon Sulfolobus solfataricus
- Creators
- Michael Rolfsmeier - George Beadle Center for Genetics, School of Biological Sciences, University of Nebraska, Lincoln, Nebraska 68588-0666Cynthia Haseltine - George Beadle Center for Genetics, School of Biological Sciences, University of Nebraska, Lincoln, Nebraska 68588-0666Elisabetta Bini - George Beadle Center for Genetics, School of Biological Sciences, University of Nebraska, Lincoln, Nebraska 68588-0666Amy Clark - George Beadle Center for Genetics, School of Biological Sciences, University of Nebraska, Lincoln, Nebraska 68588-0666Paul Blum - George Beadle Center for Genetics, School of Biological Sciences, University of Nebraska, Lincoln, Nebraska 68588-0666
- Publication Details
- Journal of bacteriology, Vol.180(5), pp.1287-1295
- Academic Unit
- Molecular Biosciences, School of
- Publisher
- American Society for Microbiology
- Identifiers
- 99900547562401842
- Language
- English
- Resource Type
- Journal article