The objective is to analyse the switch between primary metabolism during vegetative growth, and secondary metabolism and differentiation, in a model, antibiotic producing actinomycete, Streptomyces coelicolor A3(2). Understanding of this switch will have important biotechnological implications for the rational development of more efficient antibiotic producing cultures.
The project has established a consortium of laboratories with multidisciplinary skills in biochemistry physiology, genetics, and molecular biology for unified physiological and genetic studies of Streptomyces coelicolor (S. coelicolor).
Work to date has confirmed that S. coelicolor is the most suitable model antibiotic producing streptomycete to generate new insights into metabolic switching from primary to secondary metabolism.
Studies are currently being undertaken include glucose metabolic pathways, glucose transport and catabolite repression, storage compound synthesis and degradation, regulatory cascades that lead to actinorhodin production, changes in ribosome structure during development, and variations in proteins regulated by global metabolic switches.
Significant work includes methods successfully developed for reproducible assay of key enzymes of glycolysis and oxidative part of pentose phospate pathway;
evidence for regulation of PFK and PK at activity level;
isolation of presumptive CR mutants;
recognition of the GK ORF;
temporalanalysis of antibiotic gene transcripts and correlation with ppGpp;
successful analysis of adenyl cyclase;
isolation of heterologous genes that activate actinorhodin production;
purification of ActII-ORF4 protein;
identification of a putative differential by expressed ribosomal protein;
cloning of the L7/L12 gene;
recognition of families of putatively co-regulated proteins on 2D gels.
We seek an integrated view of metabolic control in a single genetically amenable streptomycete. The routes of glucose uptake and metabolism, the control of flux through these routes, and the mechanism of catabolite repression (possibly involving glucose kinase) will be.studied by physiology, biochemistry, and molecular genetics. Interactions between central metabolic regulation (catabolite repression and the stringeht response) and two kinds of secondary metabolism (actinorhodin and storage compound synthesis) will be analysed by: 2D protein gel electrophoresis; analysing carbon flux during secondary metabolism; and studying glycogen and trehalose metabolism during differentiation and antibiotic production. The regulatory pathway for actinorhodin synthesis will be mapped by analysing the effects of the actii pathway specific regulatory gene and by seeking the targets of the pleiotropic regulatory gene blda. The regulation and roles of glycogen and trehalose will be studied by cloning the relevant genes. Genes for ribosomal and other proteins shown by 2D gel analysis to have interesting regulation during growth and differentiation will be cloned and their expression studied.
Funding SchemeCSC - Cost-sharing contracts
9712 CP Groningen
1012 WX Amsterdam
CV4 7AL Coventry