Histidine dissimilation in Streptomyces coelicolor

Area of Science:

• Microbiology
• Biochemistry
• Molecular Biology

Background:

• Streptomyces coelicolor is a model organism for studying bacterial development and secondary metabolism.
• Understanding metabolic pathways is crucial for harnessing microbial capabilities.

Purpose of the Study:

• To elucidate the histidine degradation pathway in Streptomyces coelicolor.
• To identify the genes and regulatory mechanisms involved in histidine utilization.

Main Methods:

• Development of a dispersed liquid culture technique for S. coelicolor.
• Enzymatic, chromatographic, and stoichiometric analyses.
• Isolation and characterization of histidine utilization (hut) mutants.
• Haploid recombinant analysis for gene mapping.

Main Results:

• Histidine is degraded via N-formyl-L-glutamic acid in S. coelicolor.
• Histidine utilization (hut) enzymes are induced by histidine or urocanate.
• Urocanate is suggested as the physiological inducer.
• Three hut mutants were identified, with two showing uninducibility and one defective in formiminoglutamate iminohydrolase.
• Mutations were mapped to the left arm of the S. coelicolor chromosome.

Conclusions:

• A novel dispersed growth method facilitates metabolic studies in S. coelicolor.
• The histidine degradation pathway and its regulation have been characterized.
• Genetic mapping of hut genes provides insights into their chromosomal organization.