Propionigenium modestum

Schink B, N Pfennig (1982) Propionigenium modestum gen. nov., sp. nov., a new strictly anaerobic, nonspor-ing bacterium growing on succmute. Arch Microbiol 133 209-216. 

Both the synthesis of propionate and its metabolism may take place under anaerobic conditions. In Desulfobulbuspropionicum, degradation could plausibly take place by reversal of the steps used for its synthesis from acetate (Stams et al. 1984)—carboxylation of propionate to methylmalonate followed by coenzyme Bi2-mediated rearrangement to succinate, which then enters the tricarboxylic acid cycle. The converse decarboxylation of succinate to propionate has been observed in Propionigenium modestum (Schink and Pfennig 1982),... 

Dimroth, P., Wang, H., Grabe, M. and Oster, G. (1999). Energy transduction in the sodium F-ATPase of Propionigenium modestum, Proc. Natl Acad. Sci. USA, 96, 4924-4929. 

An interesting mutation is replacement of alanine 62 of the c subunit with serine. This mutant will support ATP synthase using Li+ instead of H+.237 Certain alkylophilic bacteria, such as Propionigenium modestum, have an ATP synthase that utilizes the membrane potential and a flow of Na+ ions rather than protons through the c subunits.238 240c The sodium transport requires glutamate 65, which fulfills the same role as D61 in E. coli, and also Q32 and S66. Study of mutants revealed that the polar side chains of all three of these residues bind Na+, that E65 and S66 are needed to bind Li+, and that only E65 is needed for function with H+. 

Schink, B. and N. Pfennig. 1982b. Propionigenium modestum gen. nov sp. nov a new stridly anaerobic, nonsporing baderium growing on succinate. Arch. Microbiol. 133 209-216. 

Rhodopseudomonas spheroides possible role of heme in regulation of the branched biosynthetic pathway. J Bacteriol 98 712-720 Laubinger W and Dimroth P (1987) Characterization of the Na -stimulated ATPase of Propionigenium modestum as an enzyme of the FiFq type. Eur J Biochem 168 475-480 Leaver FW, Wood HG and Stjemholm R (1955) The fermentation of three carbon substrates by Clostridium propionicum md Propionibacterium, J Bacteriol 70 521-530 Lee PC, Bochner BR and Ames BN (1983a) AppppA, heat shock stress, and cell oxidation. Proc Natl Acad Sci USA 80 7496-7500... 

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