Domain structure and function within the QUTA protein of Aspergillus nidulans: implications for the control of transcription.
QUTA is a positively acting regulatory protein that regulates the expression of the eight genes comprising the quinic acid utilization gene (qut) gene cluster in Aspergillus nidulans. It has been proposed that the QUTA protein is composed of two domains that are related to the N-terminal two domains-dehydroquinate (DHQ) synthase and 5-enolpyruvyl shikimate-3-phosphate (EPSP) synthase-of the pentadomain AROM protein. The AROM protein is an enzyme catalysing five consecutive steps in the shikimate pathway, two of which are common to the qut pathway. A genetic and molecular analysis of non-inducible qutA mutants showed that all 23 mutations analysed map within the N-terminal half of the encoded QUTA protein. One dominant mutation (qutA382) introduces a stop codon at the boundary between the two domains that were identified on the basis of amino acid sequence alignments between the QUTA protein and the N-terminal two domains of the pentafunctional AROM protein. The truncated protein encoded by mutant qutA382 has DNA-binding ability but no transcription activation function. A second dominant mutation (in strain qutA214) is missense, changing 457E-->K in a region of localized high negative charge and potentially identifies a transcription activation domain in the N-terminus of the EPSP-synthase-like domain of the QUTA protein. A series of qualitative and quantitative Northern blot experiments with mRNA derived from wild-type and mutant qutA strains supported the view that the QUTA protein regulates the expression of the qut gene cluster, including the qutA gene which encodes it. A series of Western blot and zinc-binding experiments demonstrated that a putative zinc binuclear cluster motif located within the N-terminus of the QUTA protein is able to bind zinc in vitro.
Levesley
Ian
I
Department of Genetics, Adrian Building, University of Leicester, Leicester LE1 7RH, UK.
Newton
Giles H
GH
Department of Biochemistry and Genetics, Catherine Cookson Building, New Medical School, University of Newcastle upon Tyne NE2 4HH, UK.
Lamb
Heather K
HK
Department of Biochemistry and Genetics, Catherine Cookson Building, New Medical School, University of Newcastle upon Tyne NE2 4HH, UK.
van Schothorst
Evert
E
Department of Genetics, Adrian Building, University of Leicester, Leicester LE1 7RH, UK.
Dalgleish
Raymond W M
RWM
Department of Genetics, Adrian Building, University of Leicester, Leicester LE1 7RH, UK.
Samson
Anthony C R
ACR
Department of Biochemistry and Genetics, Catherine Cookson Building, New Medical School, University of Newcastle upon Tyne NE2 4HH, UK.
Roberts
Clive F
CF
Department of Genetics, Adrian Building, University of Leicester, Leicester LE1 7RH, UK.
Hawkins
Alastair R
AR
Department of Biochemistry and Genetics, Catherine Cookson Building, New Medical School, University of Newcastle upon Tyne NE2 4HH, UK.
D051229:3-Phosphoshikimate 1-Carboxyvinyltransferase; D000429:Alcohol Oxidoreductases / Q000235:genetics; D019883:Alkyl and Aryl Transferases; D001233:Aspergillus nidulans / Q000235:genetics*; D002874:Chromosome Mapping; D018388:Codon, Terminator; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D006836:Hydro-Lyases / Q000235:genetics; D008190:Lyases / Q000235:genetics; D008667:Metalloproteins; D009097:Multienzyme Complexes / Q000235:genetics; D009154:Mutation; D010446:Peptide Fragments / Q000378:metabolism; D019761:Phosphorus-Oxygen Lyases; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics; D017434:Protein Structure, Tertiary; D011995:Recombination, Genetic; D017422:Sequence Analysis, DNA; D017384:Sequence Deletion; D015534:Trans-Activators / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic; D014166:Transferases / Q000235:genetics; D015032:Zinc / Q000378:metabolism
D018388:Codon, Terminator; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D008667:Metalloproteins; D009097:Multienzyme Complexes; D010446:Peptide Fragments; C098152:QutA protein, Aspergillus nidulans; D015534:Trans-Activators; C019728:arom enzyme; D000429:Alcohol Oxidoreductases; D014166:Transferases; D019883:Alkyl and Aryl Transferases; D051229:3-Phosphoshikimate 1-Carboxyvinyltransferase; D017853:Phosphotransferases (Alcohol Group Acceptor); D008190:Lyases; D006836:Hydro-Lyases; C020001:3-dehydroquinate synthetase; D019761:Phosphorus-Oxygen Lyases; D015032:Zinc