1887

Abstract

QUTA is a positively acting regulatory protein that regulates the expression of the eight genes comprising the quinic acid utilization gene gene cluster in 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-pyruvyl 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 pathway. A genetic and molecular analysis of non-inducible mutants showed that all 23 mutations analysed map within the N-terminal half of the encoded QUTA protein. One dominant mutation 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 has DNA-binding ability but no transcription activation function. A second dominant mutation (in strain 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 strains supported the view that the QUTA protein regulates the expression of the gene cluster, including the 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

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/content/journal/micro/10.1099/13500872-142-1-87
1996-01-01
2019-11-21
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http://instance.metastore.ingenta.com/content/journal/micro/10.1099/13500872-142-1-87
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