On the Origin of Heterotrophy

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• 作者：Peter Schö ; nheit¹ ; Wolfgang Buckel² ; ³ ; William F. Martin⁴ ; ⁵ ; ^{bill@hhu.de" class="auth_mail" title="E-mail the corresponding author}
• 关键词：autotrophic origins ; amino acid fermentations ; purine fermentations ; hydrothermal vents ; archaeal type III RubisCO
• 刊名：Trends in Microbiology
• 出版年：2016
• 出版时间：January 2016
• 年：2016
• 卷：24
• 期：1
• 页码：12-25
• 全文大小：1959 K

文摘

The theory of autotrophic origins of life posits that the first cells on Earth satisfied their carbon needs from CO₂. At hydrothermal vents, spontaneous synthesis of methane via serpentinization links an energy metabolic reaction with a geochemical homologue. If the first cells were autotrophs, how did the first heterotrophs arise, and what was their substrate? We propose that cell mass roughly similar to the composition of Escherichia coli was the substrate for the first chemoorganoheterotrophs. Amino acid fermentations, pathways typical of anaerobic clostridia and common among anaerobic archaea, in addition to clostridial type purine fermentations, might have been the first forms of heterotrophic carbon and energy metabolism. Ribose was probably the first abundant sugar, and the archaeal type III RubisCO pathway of nucleoside monophosphate conversion to 3-phosphoglycerate might be a relic of ancient heterotrophy. Participation of chemiosmotic coupling and flavin-based electron bifurcation – a soluble energy coupling process – in clostridial amino acid and purine fermentations is consistent with an autotrophic origin of both metabolism and heterotrophy, as is the involvement of S⁰ as an electron acceptor in the facilitated fermentations of anaerobic heterotrophic archaea.