Mariani Group

enzyme characterization of extremophiles

James Madison University Department of Chemistry and Biochemistry

About Us

Welcome to the Mariani Group Page!

Our group is made up of talented undergrads working on projects in protein biochemistry.


Extremophiles can be grouped according to the conditions in which they thrive. Thermophiles survive at temperatures ranging from 60C to 80C. Psychrophiles exhibit optimum growth at temperatures below 15C. In order for these microorganisms to flourish at temperature extremes, they have adopted a variety of strategies to sustain metabolic function in taxing conditions. In the case of extremophiles living in temperature extremes, the environmental stress leads to the necessity of modified cellular components including enzymes.


Homologous enzymes from mesophilic (growth between 15 and 40 C), thermophilic and psychrophilic organisms that catalyze the same reaction seem to have little variation, usually 45-65% sequence homology, which is much greater in the catalytic region. Therefore, shift in temperature optimum for enzyme catalysis is a result of several small amino acid changes that are directly related to protein stability. Comparisons of these small amino acid changes between extremophilic enzymes to their mesophilic counterparts can lead to greater insights on protein stability.


We are interested in comparing thermophilic and psychrophilic forms of several different enzymes. The enzymes we study can act as potential drug targets for antibiotics, herbicides or cancer.

James Madison University
Department of Chemistry and Biochemistry
MSC 4501; 901 Carrier Drive
Harrisonburg, VA 22807

Phone: 540-568-2355