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Project Progress

Over the past two decades, molecular biology techniques have ushered in a paradigm shift in environmental microbiology. Thriving microbial communities have been discovered inhabiting physical and chemical regimes once assumed limiting to life. These “novel” environments are collectively known as “extreme” environments and the organisms that inhabit them “extremeophiles”. As these present day environments are thought to resemble either early Earth environments in niche environments on other planets, the study of extremeophiles is of ongoing interest to several lines of inquiry related to Astrobiology. In this project, we are interested in developing a concise, molecular level understanding of how biomolecular structure allows microorganisms to adapt to various extreme aqueous environments (Figure 1).

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The specific question we are asking is: Are there identifiable protein motifs that allow for protein stability, and therefore organism survivability, which are adapted to function in particular environments? We are attempting to answer this question by applying a suite of techniques that include the development of proteomic databases, design and study of protein model molecules, and molecular characterization of extreme environments. A key aspect of protein stability is the stability of the protein structural subunits that make up the whole protein structure, the most common of which is the α-helix (Figure 2).

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One of the major ways in which an α-helix can be stabilized is by the formation of intra-helical interactions between amino acid side chains of specific compositions and positions within the helix. From the canonical 20 amino acids, there are over 3000 possible combinations that would lead to a stabilizing effect on the α-helix. Since each of these are different in their inherent strengths and response to variation in physical factors such as temperature and salt content, it is expected that organisms from different environments will show a preference for certain subsets of these interactions. We are currently undertaking a structure-function type study to catalog the frequency at which these stabilizing motifs are observed as a function of the environment of the organism from which the genomic information is obtained.