Domain interactions on the ntr signal transduction pathway: two-hybrid analysis of mutant and truncated derivatives of histidine kinase NtrB.
We have used the yeast two-hybrid system to analyze protein-protein interactions mediated by domains of regulatory proteins of the ntr signal transduction system, including interactions among NtrB derivatives and their interactions with NtrC and PII from Klebsiella pneumoniae. Interactions took place only between proteins or protein domains belonging to the ntr signal transduction system and not between proteins or domains from noncognate regulators. NtrB and its transmitter domain, but not NtrC, CheA, or the cytoplasmic C terminus of EnvZ, interacted with PII. In addition, interaction of NtrB with NtrC, but not with PII, depended on the histidine phosphotransfer domain. Point mutation A129T, diminishing the NtrC phosphatase activity of NtrB, affected the strength of the signals between NtrC and the transmitter module of NtrB but had no impact on PII signals, suggesting that A129T prevents the conformational change needed by NtrB to function as a phosphatase for NtrC, rather than disturbing binding to PII.
Martínez-Argudo
Isabel
I
División de Genética, Universidad de Alicante, Apartado 99, E-03080 Alicante, Spain.
Salinas
Paloma
P
Maldonado
Rafael
R
Contreras
Asunción
A
D001426:Bacterial Proteins; D020134:Catalytic Domain; D004268:DNA-Binding Proteins / Q000378:metabolism; D000071677:Histidine Kinase; D007711:Klebsiella pneumoniae / Q000378:metabolism*; D009154:Mutation; D009713:Nucleotidyltransferases / Q000378:metabolism; D051922:PII Nitrogen Regulatory Proteins; D010749:Phosphoprotein Phosphatases / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D017384:Sequence Deletion; D015398:Signal Transduction; D015534:Trans-Activators; D014157:Transcription Factors; D020798:Two-Hybrid System Techniques
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D051922:PII Nitrogen Regulatory Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D011494:Protein Kinases; D000071677:Histidine Kinase; C055699:protein kinase-phosphatase NTRB; D009713:Nucleotidyltransferases; C022515:regulatory protein uridylyltransferase; D010749:Phosphoprotein Phosphatases