Life's utilization of B vitamins on early Earth

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• 作者：D. R. Monteverde ; L. Gó ; mez-Consarnau ; C. Suffridge and S. A. Sañ ; udo-Wilhelmy
• 刊名：Geobiology
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：15
• 期：1
• 页码：3-18
• 全文大小：1431K
• ISSN：1472-4669

文摘

Coenzymes are essential across all domains of life. B vitamins (B₁-thiamin, B₂-riboflavin, B₃-niacin, B₅-pantothenate, B₆-pyridoxine, B₇-biotin, and B₁₂-cobalamin) represent the largest class of coenzymes, which participate in a diverse set of reactions including C₁-rearrangements, DNA repair, electron transfer, and fatty acid synthesis. B vitamin structures range from simple to complex heterocycles, yet, despite this complexity, multiple lines of evidence exist for their ancient origins including abiotic synthesis under putative early Earth conditions and/or meteorite transport. Thus, some of these critical coenzymes likely preceded life on Earth. Some modern organisms can synthesize their own B vitamins de novo while others must either scavenge them from the environment or establish a symbiotic relationship with a B vitamin producer. B vitamin requirements are widespread in some of the most ancient metabolisms including all six carbon fixation pathways, sulfate reduction, sulfur disproportionation, methanogenesis, acetogenesis, and photosynthesis. Understanding modern metabolic B vitamin requirements is critical for understanding the evolutionary conditions of ancient metabolisms as well as the biogeochemical cycling of critical elements such as S, C, and O.