Unusual oligomerization required for activity of NtrC, a bacterial enhancer-binding protein.
Nitrogen regulatory protein C (NtrC) contacts a bacterial RNA polymerase from distant enhancers by means of DNA loops and activates transcription by allowing polymerase to gain access to the template DNA strand. It was shown that NtrC from Salmonella typhimurium must build large oligomers to activate transcription. In contrast to eukaryotic enhancer-binding proteins, most of which must bind directly to DNA, some NtrC dimers were bound solely by protein-protein interactions. NtrC oligomers were visualized with scanning force microscopy. Evidence of their functional importance was provided by showing that some inactive non-DNA-binding and DNA-binding mutant forms of NtrC can cooperate to activate transcription.
Wyman
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C
Department of Plant Biology, University of California, Berkeley, CA 94720, USA.
Rombel
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I
North
A K
AK
Bustamante
C
C
Kustu
S
S
D000251:Adenosine Triphosphatases / Q000378:metabolism; D001426:Bacterial Proteins; D004269:DNA, Bacterial / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D019281:Dimerization; D004742:Enhancer Elements, Genetic; D051922:PII Nitrogen Regulatory Proteins; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D051877:RNA Polymerase Sigma 54; D012486:Salmonella typhimurium / Q000235:genetics / Q000378:metabolism; D012808:Sigma Factor / Q000378:metabolism*; D015534:Trans-Activators; D014157:Transcription Factors / Q000737:chemistry / Q000378:metabolism*; D014158:Transcription, Genetic; D015533:Transcriptional Activation
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D051922:PII Nitrogen Regulatory Proteins; D012808:Sigma Factor; D015534:Trans-Activators; D014157:Transcription Factors; D012321:DNA-Directed RNA Polymerases; D051877:RNA Polymerase Sigma 54; D000251:Adenosine Triphosphatases