An antifungal protein from Escherichia coli

1 Institute of Genomics and Integrative Biology, Mall Road, University Campus, Delhi, India 2 Department of Biotechnology, Kurukshetra University, Kurukshetra, India 3 Dr. B.R. Ambedkar Centre for Biomedical Research, Delhi, India 4 Shriram Institute for Industrial Research, Delhi, India 5 Regional Research Institute (Ay), Kothrud, Pune, India Correspondence G. L. Sharma drglsharma{at}hotmail.com Received 27 September 2006 Accepted 13 December 2006 A cytosolic protein was purified from Escherichia coli BL21 that demonstrated potent antifungal activity against pathogenic strains of Aspergillus fumigatus , Aspergillus flavus , Aspergillus niger and Candida albicans . The MIC of purified protein from E. coli BL21 (PPEBL21) against Aspergillus species and C. albicans was 1.95–3.98 and 15.62 µg ml –1 , respectively. In vitro toxicity tests demonstrated no cytotoxicity of PPEBL21 to human erythrocytes up to the tested concentrations of 1250 µg ml –1 . Amphotericin B was lethal to 100 % of human erythrocytes at a concentration of 37.5 µg ml –1 . The N-terminal amino acid sequence of PPEBL21 was found to be DLAEVASR, which showed 75 % sequence similarity with alcohol dehydrogenase of yeast. Mass fingerprinting by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry also substantiated these observations. The results suggested that E. coli BL21 might be an important bioresource of lead molecules for developing new peptide-based therapies for treating fungal infections. Abbreviations: ADH, alcohol dehydrogenase; MALDI-TOF, matrix-assisted laser desorption/ionization time-of-flight.