Characterization of Ornithine cyclodeaminase from aerococcus urinae

Details

Supervisors

Desguin, Benoît ; Ghislain, Michel

Faculty

Faculté des bioingénieurs

Degree label

Master [120] : bioingénieur en chimie et bioindustries, à finalité spécialisée

Abstract

In 2013, Professor Benoît DESGUIN and his team discovered that lactate race- mase in Lactobacillus plantarum utilizes an atypical cofactor as an alternative to the traditional NAD(P) for it’s activity. This cofactor comprises a pyridinium-3,5- dithiocarboxylic acid mononucleotide that coordinates with a nickel ion to form a pincer SCS(NiII) complex named Nickel-Pincer Nucleotide (NPN). Altough such complexes are common in organometallic chemistry, they are entirely novel in the biological world. Synthesized through a complex and unique pathway, this co- factor, characterized by its main role in hydride transfer reactions, is widespread inside the prokaryotic world. Numerous enzymes appear to be NPN-dependent, including a newly discovered family of ornithine cyclodeaminases that differ from conventional NAD-dependent ornithine cyclodeaminases from the μ-crystallin family. This report compiles the results obtained from the biochemical characteri- zation and structural observation of an unconventional ornithine cyclodeaminase found in Aerocuccus urinae, an uropathogen, which includes the unique presence of two paralogs of this family. The study aims to provide first answers concern- ing the function, the catalytic mechanism and the physiological purpose of these paralogs for the strain.