Genome-scale Metabolic Model Of Actinosynnema Pretiosum ATCC 31280 And Its Application For Ansamitocin P-3 Production Improvement

Actinosynnema pretiosum ATCC 31280 is the producer of antitumor agent ansamitocin P-3.Understanding of the AP-3 biosynthetic pathway and the whole metabolic network in Ac.pretiosum is important for the improvement of AP-3 titer.In this study,we reconstructed the first complete Genome-Scale Metabolic Model Aspm1282 for Ac.pretiosum ATCC 31280 based on the newly sequenced genome,with 87% reactions having definite functional annotation.The model has been validated by effectively predicting growth and the key genes for AP-3 biosynthesis.Then we built condition-specific models for an AP-3 high-yield mutant NXJ-24 by integrating Aspm1282 model with time-course transcriptome data.The changes of flux distribution reflect the metabolic shift from growth-related pathway to secondary metabolism pathway since the second day of cultivation.The AP-3 and methionine metabolisms were both enriched in active flux for the last two days,which indicated that up-regulation of methionine metabolic pathway is a potential strategy to improve the production of AP-3.Furthermore,we identified 3 combinatorial gene modifications for overproducing AP-3 by in silico strain design.In this study,we reconstructed and validated the first genome-scale metabolic model Aspm1282.Then we reconstructed four condition-specific metabolic models by integrating Aspm1282 model with time-course transcriptome data.By analyzing the models,we observe the changes of metabolic pattern during the fermentation process,found that the methionine metabolism pathway is important for improvement of AP-3 product and identified five modification strategies for overproducing AP-3.The genome-scale model of Ac.pretiosum ATCC 31280 is an important resource for systems biology study of actinomycetes.This study is of important significance guiding secondary metabolism engineering for actinomycetes.