A new transcriptional activator for amylase genes in Aspergillus

Petersen, Katrin; Lehmbeck, Jan; Christensen, Tove

doi:10.1007/s004380051129

Cited by 111 publications

(100 citation statements)

References 38 publications

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“…The potential involvement of nitrogen metabolism in amylase production was assessed. It is another mode of the amylase enzyme expression system, which is different from the conventional mode previously explained for AmyR [12][13][14] and CreA, 15,16) and in another aspect different from the glycogen-related metabolism in the mycelia. 17,18) On the basis of the above-described assessment results, the following hypothesis that might explain the high enzyme production by A. oryzae in the submerged culture with UWB was considered: First, in the first half of the period of culture using MWB, rapid glucose release from the raw material owing to milling activates glycolysis.…”

Section: Gene Expression Analysismentioning

confidence: 71%

Analysis of Enzyme Production by Submerged Culture ofAspergillus oryzaeUsing Whole Barley

Masuda

Kikuchi

Matsumoto

et al. 2009

Bioscience, Biotechnology, and Biochemistry

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Section: Gene Expression Analysismentioning

confidence: 71%

Analysis of Enzyme Production by Submerged Culture ofAspergillus oryzaeUsing Whole Barley

Masuda

Kikuchi

Matsumoto

et al. 2009

Bioscience, Biotechnology, and Biochemistry

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“…For instance, secretion of GlaA (Wösten et al 1991) and expression of its encoding gene glaA (Levin et al 2007a) mainly take part at the periphery of the colony. AmyR regulates expression of glaA and other genes encoding enzymes that are active on glucose-and galactose-containing oligo-and polysaccharides (Petersen et al 1999;vanKuyk et al 2011).…”

Section: Introductionmentioning

confidence: 99%

FluG affects secretion in colonies of Aspergillus niger

Wang

Krijgsheld

Hulsman

et al. 2014

Antonie van Leeuwenhoek

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Colonies of Aspergillus niger are characterized by zonal heterogeneity in growth, sporulation, gene expression and secretion. For instance, the glucoamylase gene glaA is more highly expressed at the periphery of colonies when compared to the center. As a consequence, its encoded protein GlaA is mainly secreted at the outer part of the colony. Here, multiple copies of amyR were introduced in A. niger. Most transformants over-expressing this regulatory gene of amylolytic genes still displayed heterogeneous glaA expression and GlaA secretion. However, heterogeneity was abolished in transformant UU-A001.13 by expressing glaA and secreting GlaA throughout the mycelium. Sequencing the genome of UU-A001.13 revealed that transformation had been accompanied by deletion of part of the fluG gene and disrupting its 3 0 end by integration of a transformation vector. Inactivation of fluG in the wild-type background of A. niger also resulted in breakdown of starch under the whole colony. Asexual development of the DfluG strain was not affected, unlike what was previously shown in Aspergillus nidulans. Genes encoding proteins with a signal sequence for secretion, including part of the amylolytic genes, were more often downregulated in the central zone of maltose-grown DfluG colonies and upregulated in the intermediate part and periphery when compared to the wild-type. Together, these data indicate that FluG of A. niger is a repressor of secretion.Keywords Fungus Á Conidiogenesis Á Asexual development Á Aspergillus fluG Á Secretion Á Heterogeneity Electronic supplementary material The online version of this article

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“…The expression levels of extracellular starch-degrading enzymes are generally increased during growth in the presence of maltose or isomaltose. This system is particularly well studied in aspergilli, in which expression of these enzymes is regulated by AmyR (Petersen et al, 1999;Tani et al, 2001;Nakamura et al, 1997).…”

Section: Introductionmentioning

confidence: 99%

Phylogenetic and biochemical characterization of a novel cluster of intracellular fungal α-amylase enzymes

et al. 2007

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Currently known fungal a-amylases are well-characterized extracellular enzymes that are classified into glycoside hydrolase subfamily GH13_1. This study describes the identification, and phylogenetic and biochemical analysis of novel intracellular fungal a-amylases. The phylogenetic analysis shows that they cluster in the recently identified subfamily GH13_5 and display very low similarity to fungal a-amylases of family GH13_1. Homologues of these intracellular enzymes are present in the genome sequences of all filamentous fungi studied, including ascomycetes and basidiomycetes. One of the enzymes belonging to this new group, Amy1p from Histoplasma capsulatum, has recently been functionally linked to the formation of cell wall a-glucan. To study the biochemical characteristics of this novel cluster of a-amylases, we overexpressed and purified a homologue from Aspergillus niger, AmyD, and studied its activity product profile with starch and related substrates. AmyD has a relatively low hydrolysing activity on starch (2.2 U mg "1 ), producing mainly maltotriose. A possible function of these enzymes in relation to cell wall a-glucan synthesis is discussed. INTRODUCTIONa-Amylases are widely occurring enzymes which hydrolyse the a-(1,4)-glycosidic bonds in starch and glycogen, producing short maltooligosaccharides and maltose. Based on sequence similarity, most a-amylases (EC 3.2.1.1) are classified in glycoside hydrolase (GH) family 13, although some a-amylases originating from extremophilic organisms belong to family GH57 (Henrissat, 1991;Henrissat & Bairoch, 1996) (see also the CAZy website, http://www.cazy.org). Based on a phylogenetic analysis of 1691 different members of the GH13 family, the family has recently been divided into 35 subfamilies, all acting on aglycosidic bonds (Stam et al., 2006). Several of these subfamilies display a-amylase specificity, but many other enzyme reaction specificities are also represented. The tertiary structure of these enzymes is characterized by a (b/a) 8 barrel containing four highly conserved amino acid regions that form the active site (MacGregor et al., 2001), but the overall sequence similarity can be as low as 10 % and only a catalytic triad of amino acids is conserved invariantly (Machovic & Janecek, 2003). The shared (b/a) 8 barrel structure and catalytic mechanism within GH13 enzymes are believed to represent a common evolutionary origin (Kuriki & Imanaka, 1999;Janecek, 1997). The presence of the four conserved regions and a common secondary and tertiary structure allow construction of alignments and phylogenetic studies within the family. The phylogeny of a-amylases is generally in agreement with their origin, e.g. all fungal a-amylases are more related to each other than to the a-amylases originating from plants or animals. a-Amylases from bacteria, however, are scattered over several clusters, which group with animal, plant or fungal a-amylases, or form a separate branch (Janecek, 1994).Several a-amylases from yeasts and fungi have been studied previously (see e.g....

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A new transcriptional activator for amylase genes in Aspergillus

Cited by 111 publications

References 38 publications

Analysis of Enzyme Production by Submerged Culture ofAspergillus oryzaeUsing Whole Barley

Analysis of Enzyme Production by Submerged Culture ofAspergillus oryzaeUsing Whole Barley

FluG affects secretion in colonies of Aspergillus niger

Phylogenetic and biochemical characterization of a novel cluster of intracellular fungal α-amylase enzymes

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