Líffræðifélag Íslands - biologia.is
Líffræðiráðstefnan 2019

Erindi/veggspjald / Talk/poster V22

Characterization of critical glycolytic enzyme paralogs within the symbiotic cyanobacterium Nostoc sp. N6

Höfundar / Authors: Kári M. Ásdísarson, Ólafur S. Andrésson, Denis Warshan

Starfsvettvangur / Affiliations: Faculty of Life and Environmental Sciences, University of Iceland.

Kynnir / Presenter: Kári M. Ásdísarson, Ólafur S. Andrésson

Recent genome analysis of Nostoc cyanobacteria has revealed an alternative version of glucose 6-phosphate dehydrogenase (zwf) and a shortened homolog of 6-phosphogluconate dehydrogenase (gnd), enzymes which route catabolism down the Entner-Doudoroff (ED) and pentose phosphate (PP) pathways. Genes encoding 6-phosphofructokinase (pfkA), an early enzyme in the Embden-Meyerhof pathway (EM), were found to be pseudogenes in several strains, indicating that these strains make use of the ED and PP pathways rather than the classical EM pathway for glycolysis. As the ED and PP pathways can be the primary means of catabolism within cyanobacteria variations in these enzymes warrant additional research.
This study focuses on the duplicates of these dehydrogenases carried by many cyanobacteria and whether they possess any unique characteristics. The duplicated genes were isolated from the Nostoc sp. N6 genome via PCR and assembled onto a His-tagged T7 expression vector via Gibson assembly. The assembled vector was then transformed into protein expression strains from which the enzymes will be isolated for kinetic analysis.
Currently, enzyme purification is being optimized. Preliminary results of kinetic analysis will be presented if available, along with phylogenetic analysis conducted on the G6PD duplicate which was found to be shared with Gloeobacter (G. violaceus and G. kilaueensis), the sister group of all cyanobacteria that split off over 3 billion years ago, hinting at an ancient origin of the duplicate.