kouril5

Title

Phosphoglycerate kinase acts as a futile cycle at high temperature

Authors

Theresa Kouril,1,2 Johann J. Eicher,2 Bettina Siebers1 and Jacky L. Snoep2,3,4,*

Affiliations

1Molecular Enzyme Technology and Biochemistry (MEB), BiofilmCentre, Faculty of Chemistry, University of Duisburg-Essen, Duisburg, Germany; 2Department of Biochemistry, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa; 3Molecular Cell Physiology, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands; 4MIB, University of Manchester, Manchester, UK.

Abstract

In (hyper)thermophilic organisms metabolic processes have to be adapted to function optimally at high temperature. We compared the gluconeogenetic conversion of 3-phosphoglycerate via 1,3-bisphosphoglycerate to glyceraldehyde-3-phosphate at 30 C and at 70 C. At 30 C it was possible to produce 1,3-bisphosphoglycerate from 3-phosphoglycerate, but at 70 C, 1,3- bisphosphoglycerate was dephosphorylated rapidly to 3-phosphoglycerate, effectively turning the phosphoglycerate kinase into a futile cycle. When phosphoglycerate kinase was incubated together with glyceraldehyde 3-phosphate dehydrogenase it was possible to convert 3-phosphoglycerate to glyceraldehyde 3-phosphate, both at 30 C and at 70 C, however, at 70 C only low concentrations of product were observed due to thermal instability of glyceraldehyde 3-phosphate. Thus, thermolabile intermediates challenge central metabolic reactions and require special adaptation strategies for life at high temperature.

Journal

Microbiology

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