CO^sub 2^-Formatics: How Do Proteins Bind Carbon Dioxide?

The rising atmospheric concentration of CO^sub 2^ has motivated researchers to seek routes for improved utilization, increased mitigation, and enhanced sequestration of this greenhouse gas. Through a combination of bioinformatics, molecular modeling, and first-principles quantum mechanics the binding of carbon dioxide to proteins is analyzed. It is concluded that acid/base interactions are the principal chemical force by which CO^sub 2^ is bound inside proteins. With respect to regular secondary structural elements, β-sheets show a marked preference for CO^sub 2^ binding compared to a-helices. The data also support the inference that while either or both oxygens of CO^sub 2^ are generally tightly bound in the protein environment, the carbon is much less "sequestered." First principles and more approximate modeling techniques are assessed for quantifying CO^sub 2^ binding thermodynamics. [PUBLICATION ABSTRACT]