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dc.contributor.author Gordon, Gina C.
dc.contributor.author McKinlay, James B.
dc.date.accessioned 2018-07-05T16:46:21Z
dc.date.available 2018-07-05T16:46:21Z
dc.date.issued 2014-01
dc.identifier.citation Gordon, GC and JB McKinlay. 2014. Calvin cycle mutants of photoheterotrophic purple non-sulfur bacteria fail to grow due to an electron imbalance rather than toxic metabolite accumulation. Journal of Bacteriology. 196: 1231-1237. en
dc.identifier.uri https://hdl.handle.net/2022/22258
dc.description Post-print, accepted manuscript version en
dc.description.abstract Purple nonsulfur bacteria grow photoheterotrophically by using light for energy and organic compounds for carbon and electrons. Disrupting the activity of the CO$_2$-fixing Calvin cycle enzyme, ribulose 1,5-bisphosphate carboxylase (RubisCO), prevents photoheterotrophic growth unless an electron acceptor is provided or if cells can dispose of electrons as H$_2$. Such observations led to the long-standing model wherein the Calvin cycle is necessary during photoheterotrophic growth to maintain a pool of oxidized electron carriers. This model was recently challenged with an alternative model wherein disrupting RubisCO activity prevents photoheterotrophic growth due to the accumulation of toxic ribulose-1,5-bisphosphate (RuBP) (D. Wang, Y. Zhang, E. L. Pohlmann, J. Li, and G. P. Roberts, J. Bacteriol. 193:3293-3303, 2011, http://dx.doi.org/10.1128/JB.00265-11). Here, we confirm that RuBP accumulation can impede the growth of Rhodospirillum rubrum (Rs. rubrum) and Rhodopseudomonas palustris (Rp. palustris) RubisCO-deficient (ΔRubisCO) mutants under conditions where electron carrier oxidation is coupled to H$_2$ production. However, we also demonstrate that Rs. rubrum and Rp. palustris Calvin cycle phosphoribulokinase mutants that cannot produce RuBP cannot grow photoheterotrophically on succinate unless an electron acceptor is provided or H$_2$ production is permitted. Thus, the Calvin cycle is still needed to oxidize electron carriers even in the absence of toxic RuBP. Surprisingly, Calvin cycle mutants of Rs. rubrum, but not of Rp. palustris, grew photoheterotrophically on malate without electron acceptors or H$_2$ production. The mechanism by which Rs. rubrum grows under these conditions remains to be elucidated. en
dc.language.iso en en
dc.publisher Journal of Bacteriology en
dc.relation.isversionof http://jb.asm.org/content/196/6/1231.full en
dc.title Calvin cycle mutants of photoheterotrophic purple non-sulfur bacteria fail to grow due to an electron imbalance rather than toxic metabolite accumulation en
dc.type Article en
dc.identifier.doi 10.1128/JB.01299-13


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