Structure-function relationships of anaerobic gas-processing metalloenzymes.

Reactions involving H(2), N(2), CO, CO(2) and CH(4) are likely to have been central to the origin of life. This is indicated by the active-site structures of the enzymes involved, which are often reminiscent of minerals. Through the combined efforts of protein crystallography, various types of spectroscopy, theoretical calculations and model chemistry, it has been possible to put forward plausible mechanisms for gas-based metabolism by extant microorganisms. Although the reactions are based on metal centres, the protein matrix regulates reactivity and substrate and product trafficking through internal pathways, specific ligation and dielectricity.