Mechanistic and Biosynthetic Studies of Methanogenesis and Bioluminescence
Dr. Steven Mansoorabadi; Assistant Professor, Auburn University
September 8 in the Fralin Auditorium, Fralin Hall 102
Hosted by Dr. Pablo Sobrado
This seminar will highlight recent work in the Mansoorabadi laboratory focused on the chemistry and biochemistry of tetrapyrroles. Tetrapyrroles, the ‘pigments of life’, are an important class of biomolecules that play essential roles in several fundamental biological processes, including methanogenesis (coenzyme F430) and bioluminescence (dinoflagellate luciferin).
Coenzyme F430 is the highly reduced, nickel-containing prosthetic group of methyl-coenzyme M reductase (MCR), the key methane-forming enzyme of methanogenic archaea. Homologs of MCR have also been identified in anaerobic methanotrophic archaea, which utilize coenzyme F430 for the anaerobic oxidation of methane. Methane is a potent greenhouse gas and biofuel, and MCR holds much promise for use in methane bioconversion strategies. However, a lack of genetic and biochemical information about the biosynthesis of coenzyme F430 and the formation of holo MCR have hampered metabolic engineering efforts utilizing MCR. The first part of the seminar will cover current progress and remaining challenges in this area.
Dinoflagellates are an important group of eukaryotic microorganisms found in freshwater and marine environments. Certain species produce toxins and are responsible for red tides, while others are capable of both photosynthesis and bioluminescence. The bioluminescence system of dinoflagellates, which is regulated on a circadian rhythm, consists of a pH-regulated enzyme, dinoflagellate luciferase, and a luminescent substrate, dinoflagellate luciferin, which is a degradation product of the tetrapyrrole chlorophyll. Of all the major classes of luciferase, least is known about the mechanism of dinoflagellate luciferase. The second part of the seminar will focus on recent insight into the mechanism of light production and pH-dependent activation of dinoflagellate luciferase.