Mechanistic and Biosynthetic Studies of Dinoflagellate Bioluminescence

Friday, November 8, 2019

Dr. Steven O. Mansoorabadi

Department of Chemistry and Biochemistry

Auburn University

Abstract: Dinoflagellates are an important group of eukaryotic microorganisms found in freshwater and marine environments. Certain dinoflagellates produce potent toxins that are the causative agents of diarrheic, amnesic, paralytic, and neurotoxic shellfish poisonings, and are responsible for the formation of harmful algal blooms (red tides). Still other dinoflagellates are capable of both photosynthesis and bioluminescence, processes that are regulated by a cellular circadian rhythm (biological clock) and give rise to bioluminescent bays and the ‘phosphorescence’ of the sea. The key, light-forming enzyme of dinoflagellate bioluminescence, dinoflagellate luciferase (LCF), contains three homologous catalytic domains within a single polypeptide and is tightly regulated by pH. The production of blue-green light by LCF is coupled to the oxidation of an open-chain tetrapyrrolic substrate, dinoflagellate luciferin (LH2), which is a catabolite of the photosynthetic pigment chlorophyll. Current progress in our understanding of LH2 biosynthesis and the chemiluminescent and pH-dependent activation mechanisms of LCF will be presented.

Bio: Dr. Mansoorabadi was born and raised in Milwaukee, WI. He received a B.S. degree in Biological Sciences, Chemistry, and Applied Mathematics & Physics, and a P.B.C. in Biotechnology, from the University of Wisconsin – Milwaukee. He performed his graduate studies at the University of Wisconsin – Madison, where he worked at the Institute for Enzyme Research under the supervision of Prof. George H. Reed and received his Ph.D. degree in Biochemistry. Dr. Mansoorabadi then moved to The University of Texas at Austin, where he was a NIH Ruth L. Kirschstein postdoctoral fellow in the laboratory of Prof. Hung-wen (Ben) Liu. Dr. Mansoorabadi began his independent career at Auburn University in 2012.

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