Protein Profiling of Wild-type Neurospora crassa Grown on Various Carbon Sources

Abstract

Neurospora crassa possesses characteristics that make an ideal model for eukaryotic organisms. N. crassa metabolizes preferred carbon sources such as dextrose, but has the ability to metabolize less preferred carbon sources such as quinic acid or glycerol. This study analyzes the protein profiles of wild-type N. crassa grown on 2% dextrose, 2% glycerol, and 0.3% quinic acid. To perform the study, N. crassa was grown on Vogels minimal media and shifted to various carbon sources. Protein was extracted from N. crassa tissue and ran on two-dimensional gel electrophoresis (2-DGE). The 2-D gels were imaged and analyzed utilizing PDQuest [trade mark]. Protein spots of interest were excised from the 2-D gels and sequenced by capillary-liquid chromatography-nanospray tandem mass spectrometry. Protein identifications were determined by searching SwissProt and NCBI databases for homologous fungal sequences. The study revealed that more protein was expressed on the preferred carbon source, dextrose, compared to the less preferred carbon sources, quinic acid and glycerol. Unique protein expression patterns were also generated for each of the carbon sources. The identified proteins found to be unique to dextrose included an ATP-dependent RNA helicase, an enolase, and a cytochrome c peroxidase. A probable pyridoxine biosynthesis protein was established to be unique to glycerol, while a peptidyl-prolyl cis-tans isomerase and a Cu-Zn superoxide dismutase were determined to be unique to quinic acid.