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Title: Difference in C3–C4 metabolism underlies tradeoff between growth rate and biomass yield in Methylobacterium extorquens AM1

In this study, two variants of Methylobacterium extorquens AM1 demonstrated a trade-off between growth rate and biomass yield. In addition, growth rate and biomass yield were also affected by supplementation of growth medium with different amounts of cobalt. The metabolism changes relating to these growth phenomena as well as the trade-off were investigated in this study. 13C metabolic flux analysis was used to generate a detailed central carbon metabolic flux map with both absolute and normalized flux values. As a result, the major differences between the two variants occurred at the formate node as well as within C3-C4 inter-conversion pathways. Higher relative fluxes through formyltetrahydrofolate ligase, phosphoenolpyruvate carboxylase, and malic enzyme led to higher biomass yield, while higher relative fluxes through pyruvate kinase and pyruvate dehydrogenase led to higher growth rate. These results were then tested by phenotypic studies on three mutants (null pyk, null pck mutant and null dme mutant) in both variants, which agreed with the model prediction. In this study, 13C metabolic flux analysis for two strain variants of M. extorquens AM1 successfully identified metabolic pathways contributing to the trade-off between cell growth and biomass yield. Phenotypic analysis of mutants deficient in corresponding genes supported the conclusionmore » that C3-C4 inter-conversion strategies were the major response to the trade-off.« less
Authors:
; ;
Publication Date:
OSTI Identifier:
1299217
Grant/Contract Number:
SC0006871
Type:
Accepted Manuscript
Journal Name:
BMC Microbiology
Additional Journal Information:
Journal Volume: 16; Journal Issue: 1; Journal ID: ISSN 1471-2180
Publisher:
BioMed Central
Research Org:
Univ. of Washington, Seattle, WA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES Methylobacterium extorquens AM1; Methylotrophy; physiological trade-off; metabolic flux analysis; cobalt; flux analysis; labeling experiments; reconstruction; methanol; formate; point