Proteomic Analysis Of Streptomyces Lydicus During Antifungal Antibiotic Production

To well-understand the growth and production of Streptomyces lydicus AS 4.2501 from shake flask to 30L fermentor during antifungal activities production, we investigated the capability of antifungal activities, changes in intracellular and extracellular proteome, and low-molecular metabolites. Results are as following:The antifungal bioactivity of extracellular componds and intercellular componds of S. lydicus AS 4.2501 and S. lydicus E9 were examined. Whether extracellular compounds or intracellular compounds, the bioactivity of S. lydicus E9 is much higher than that of AS 4.2501.2-DE analysis showed that there is significant difference in intra- and extra-cellular proteins between S. lydicus AS 4.2501 and S. lydicus E9. The 22 significantly expressed proteins were identified using MALDI-TOF-MS. These proteins are associated with bioprocesses of gene transcription, carbohydrate metabolism, phospholipid metabolism, and biosynthesis of antifungal antibiotic, such as tetR family transcriptional regulator, ATP-dependent Clp protease proteolytic subunit, phosphoglyceromutase, phospholipase, deoxyuridine 5'-triphosphate nucleotidohydr-olase, polyphosphate glucokinase, glucose-6-phosphate-1-dehydrogenase, and so on.Intercellular and extracellular proteome of S. lydicus E9 in 2L and 30L fermentor were further investigated. 2-DE profiles were different in different fermentors at different culture stages. The 23 proteins including carboxylase, cetyl-CoA acetyltransferase, acetyltransferase, ornithine carbamoyltransferase, adenine phosphoribosyltransferase, and glutamine synthetase were identified. The identified proteins were related to the polyketide pathway. Therefore, we presume that the polyketide pathway was possible the main biosynthetic pathway of this antifungal antibiotic.The low-molecular metabolites of S. lydicus were primarily explored using GC-TOF-MS. PCA analysis reveal 5 metabolites corresponding to glycerol , butanetetrol, D-Galactose, glucitol, D-Turanose. Possible roles of them will further inveatigated.