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2006 Annual Science Report

Pennsylvania State University Reporting  |  JUL 2005 – JUN 2006

Oxygen Metabolism and Oxidatie Stress in Anaerobic Microorganisms (Ferry)

4 Institutions
3 Teams
0 Publications
0 Field Sites
Field Sites

Project Progress

Although wide spread among anaerobic procaryotes, a physiological function for a recently described flavoprotein family (iron-sulfur flavoprotein (Isf)) was unknown. We determined that Isf from the methane-producing archaeon Methanosarcina thermophila is able to reduce O2 and H2O2 to water, thereby detoxifying these reactive oxygen species and protecting the organism from oxidative stress. We also showed that tryptophan repressor binding protein (WrbA), previously hypothesized to be a regulatory protein, is a quinone reductase which reduces quinones to the fully-reduced state avoiding the semiquinone that interacts with O2 to produce toxic superoxide radicals. Thus, the function of two new families of proteins have been determined to be involved in the oxidative stress response of anaerobic procaryotes from the Bacteria and Archaea domains. A further understanding of the ancient gamma-class carbonic anhydrase was accomplished that sheds light on the evolution of this class and how it functions in the methane-producing Archaea. Finally, together with Christopher House, we developed a novel theory for early evolution of the cell. In contrast to current paradigms, we proposed that an energy-conservation pathway was the major force which powered and directed early evolution. We further proposed that energy conservation played the predominant role in the later evolution of anaerobic metabolisms which explains the origin and evolution of extant methanogenic pathways.

    James Ferry James Ferry
    Project Investigator
    Christopher House

    Daniel Lessner

    Frank Cruz
    Doctoral Student

    Eric Patridge
    Doctoral Student

    Sabrina Zimmerman
    Doctoral Student

    Objective 3.3
    Origins of energy transduction

    Objective 4.1
    Earth's early biosphere

    Objective 4.2
    Foundations of complex life

    Objective 5.1
    Environment-dependent, molecular evolution in microorganisms

    Objective 6.1
    Environmental changes and the cycling of elements by the biota, communities, and ecosystems