BEGIN:VCALENDAR
VERSION:2.0
X-WR-CALNAME;VALUE=TEXT:Professor Eric Boyd (Montana State University) - "Overcoming Thermodynamic and Biosynthetic Limitations at the Origin of Life"
PRODID:-//Harvard events data//EN
BEGIN:VEVENT
UID:event_1113197_0
SUMMARY:Professor Eric Boyd (Montana State University) - "Overcoming Thermodynamic and Biosynthetic Limitations at the Origin of Life"
DESCRIPTION:Abstract: <p>	Hydrogen (H<sub>2</sub>) serves as a key point of interface between the geosphere and the biosphere and has likely done so since early in the history of Earth. Indeed, many of the most well accepted origin of life scenarios involve autotrophic microbial metabolisms that are fueled by redox reactions involving H<sub>2</sub>, including the processes of acetogenesis and methanogenesis. Acetogens and methanogens use the iron sulfur (Fe-S) protein ferredoxin (Fd) to facilitate key electron transfers between H<sub>2</sub> and carbon reduction. However, the redox potential of H<sub>2</sub> (E<sup>0</sup> = -420 mV) is not of sufficiently negative potential to drive reduction of Fd (E<sup>0</sup> = -500 mV). Here we will examine mechanisms that allow for the reduction of Fd with H<sub>2</sub> in primitive cells, with a focus on the process of electron bifurcation (EB). EB <span lang="EN" style="line-height:107%"><span style="color:black">involves the simultaneous reduction or oxidation of two electron acceptors in an enzyme complex, whereby a thermodynamically favorable exergonic reaction drives a thermodynamically unfavorable endergonic reaction. </span></span><span style="line-height:107%">Along with substrate level and oxidative phosphorylation, EB has been proposed as the third fundamental mechanism by which energy can be conserved in biological systems. Phylogenetic analyses, combined with taxonomic distribution data, are used to evaluate the ancestry of EB enzyme complexes and their role in life’s earliest metabolisms. Environmental conditions that putatively supported the earliest evolving organisms and their EB complexes are proposed. Finally, we briefly examine novel pathways that acetogens and methanogens may have used to acquire iron and sulfur to meet Fe-S biosynthetic demands in these environments.</span></p>
LOCATION:Haller Hall, Geological Museum, 24 Oxford Street
STATUS:CONFIRMED
DTSTART:20180418T200000Z
DTEND:20180418T213000Z
END:VEVENT
END:VCALENDAR