An operator binding-negative mutation of Xyl repressor from Bacillus subtilis is trans dominant in Bacillus megaterium |
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Authors: | Christine Kauder Rudolf Allmansberger Dagmar Gärtner Dagmar Schmiedel Wolfgang Hillen |
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Institution: | Lehrstuhl für Mikrobiologie, Institut für Mikrobiologie und Biochemie der Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, FRG |
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Abstract: | Abstract We have selected a Bacillus subtilis 168-borne xylR Ser to Leu mutation at position 41 of the encoded amino acid sequence showing a constitutive expression phenotype for the xyl operon. When cloned on a multi-copy plasmid in a B. megaterium strain harbouring a single-copy xylA-lacZ fusion it leads to derepressor of β-galactosidase expression. Thus, it is trans dominant over the endogenous xylR , indicating that Xyl repressor functions as a multimer. This result also supports the assumption that the mutation is in a putative α-helix-turn-α-helix operator binding motif of Xyl repressor. |
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Keywords: | α-Helix-turn-α-helix motif Xylose utilization Mutagenesis Xyl repressor Bacillus subtilis Bacillus megaterium |
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