The genome of Syntrophus aciditrophicus: Life at the thermodynamic limit of microbial growth

摘要: Biochemically, the syntrophic bacteria constitute missing link in our understanding of anaerobic flow carbon biosphere. The completed genome sequence Syntrophus aciditrophicus SB, a model fatty acid- and aromatic acid-degrading bacterium, provides glimpse composition architecture electron transfer energy-transducing systems needed to exist on marginal energy economies lifestyle. contains 3,179,300 base pairs 3,169 genes where 1,618 were assigned putative functions. Metabolic reconstruction gene inventory revealed that most biosynthetic pathways typical Gram-negative microbe present. A distinctive feature metabolism is need for reverse transport; presence unique Rnf-type ion-translocating complex, menaquinone, membrane-bound Fe-S proteins with associated heterodisulfide reductase domains suggests mechanisms accomplish this task. Previously undescribed approaches degrade acids, including multiple AMP-forming CoA ligases acyl-CoA synthetases seem be present as ways form dissipate ion gradients by using sodium-based strategy. Thus, S. aciditrophicus, although nutritionally self-sufficient, seems specialist limited fermentative respiratory metabolism. Genomic analysis confirms metabolic regulatory commitment nonconventional mode life compared prevailing microbiology.