Carbon Catabolite Repression and the Related Genes of ccpA, ptsH and hprK in Thermoanaerobacterium aotearoense

PLoS One. 2015 Nov 5;10(11):e0142121. doi: 10.1371/journal.pone.0142121. eCollection 2015.

Abstract

The strictly anaerobic, Gram-positive bacterium, Thermoanaerobacterium aotearoense SCUT27, is capable of producing ethanol, hydrogen and lactic acid by directly fermenting glucan, xylan and various lignocellulosically derived sugars. By using non-metabolizable and metabolizable sugars as substrates, we found that cellobiose, galactose, arabinose and starch utilization was strongly inhibited by the existence of 2-deoxyglucose (2-DG). However, the xylose and mannose consumptions were not markedly affected by 2-DG at the concentration of one-tenth of the metabolizable sugar. Accordingly, T. aotearoense SCUT27 could consume xylose and mannose in the presence of glucose. The carbon catabolite repression (CCR) related genes, ccpA, ptsH and hprK were confirmed to exist in T. aotearoense SCUT27 through gene cloning and protein characterization. The highly purified Histidine-containing Protein (HPr) could be specifically phosphorylated at Serine 46 by HPr kinase/phosphatase (HPrK/P) with no need to add fructose-1,6-bisphosphate (FBP) or glucose-6-phosphate (Glc-6-P) in the reaction mixture. The specific protein-interaction of catabolite control protein A (CcpA) and phosphorylated HPr was proved via affinity chromatography in the absence of formaldehyde. The equilibrium binding constant (KD) of CcpA and HPrSerP was determined as 2.22 ± 0.36 nM by surface plasmon resonance (SPR) analysis, indicating the high affinity between these two proteins.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / genetics*
  • Carbon / metabolism*
  • Catabolite Repression / genetics*
  • DNA-Binding Proteins / genetics
  • Gene Expression Regulation, Bacterial / genetics
  • Glucose-6-Phosphate / genetics
  • Histidine / genetics
  • Metabolism / genetics*
  • Phosphoenolpyruvate Sugar Phosphotransferase System / genetics*
  • Protein Serine-Threonine Kinases / genetics*
  • Thermoanaerobacterium / genetics*

Substances

  • Bacterial Proteins
  • DNA-Binding Proteins
  • Histidine
  • Glucose-6-Phosphate
  • Carbon
  • Phosphoenolpyruvate Sugar Phosphotransferase System
  • HPr kinase
  • Protein Serine-Threonine Kinases

Grants and funding

This study was supported by research grants from the National Natural Science Foundation of China (21276096), International Cooperation Research Program of Guangdong, China (2014A050503024), the Natural Science Foundation of Guangdong, China (2014A030313258) and the Fundamental Research Funds for the Central Universities, SCUT. Shuang Li was funded by the Pearl River New-Star of Science & Technology supported by Guangzhou City (2012J2200012). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.