Profiling the Monascus pilosus proteome during nitrogen limitation.
Monascus species have the unique ability to economically produce many secondary metabolites. However, the influence of nitrogen limitation on Monascus secondary metabolite production and metabolic performance remains unclear. Varying the carbon/nitrogen (C/N) ratios in the range from 20 to 60 in cultivation of Monascus pilosus by glucose nitrate medium, our resulting data showed that red pigment production was significantly suppressed and more sensitive to nitrogen limitation than cellular biomass growth at a C/N ratio of 60. Using a comparative proteomic approach, combining two-dimensional gel electrophoresis, matrix-assisted laser desorption ionization time-of-flight/time-of-flight liquid chromatography-mass spectrometry, and tandem mass spectrometry, proteins with modified expression in the nitrogen-limited (C/N ratio 60) Monascus filamentous cells were identified. The results revealed that the deregulated proteins identified were involved in amino acid biosynthesis, protein translation, antioxidant-related enzymes, glycolysis, and transcriptional regulation. The results suggested that, under nitrogen limitation-induced suppression of protein translation and of expression of the related energy-generating enzymes, nitrogen limitation induced a switch of metabolic flux from glycolysis to the tricarboxylic acid (TCA) cycle for maintaining cellular energy homeostasis, resulting in repression of the metabolic shift of the polyketide biosynthesis pathway for red pigment production.
Lin
Wun-Yuan
WY
Department of Food Science, Nutrition, and Nutraceutical Biotechnology, Shih Chien University, Taipei, Taiwan.
Chang
Jui-Yun
JY
Hish
Chih-Hsuan
CH
Pan
Tzu-Ming
TM
D000595:Amino Acid Sequence; D002952:Citric Acid Cycle; D004734:Energy Metabolism; D005656:Fungal Proteins / Q000032:analysis / Q000737:chemistry; D006019:Glycolysis; D008969:Molecular Sequence Data; D032741:Monascus / Q000737:chemistry / Q000254:growth & development* / Q000378:metabolism*; D009584:Nitrogen / Q000008:administration & dosage*; D010860:Pigments, Biological / Q000096:biosynthesis; D020543:Proteome / Q000032:analysis*
D005656:Fungal Proteins; D010860:Pigments, Biological; D020543:Proteome; D009584:Nitrogen