Journal article
Folate polyglutamylation eliminates dependence of activity on enzyme concentration in mitochondrial serine hydroxymethyltransferases from Arabidopsis thaliana
Archives of biochemistry and biophysics, Vol.536(1), pp.87-96
08/01/2013
Handle:
https://hdl.handle.net/2376/113054
PMID: 23800877
Abstract
•Three recombinant SHMTs from A. thaliana (AtSHMTs) were characterized.•Two enzymes faster at higher enzyme concentrations with monoglutamate folates.•The effect absent in the presence of pentaglutamate folate substrates.•No evidence for a change in the oligomerization state.
The reversible reaction catalyzed by serine hydroxymethyltransferase (SHMT) is the major one-carbon unit source for essential metabolic processes. The Arabidopsis thaliana genome encodes seven SHMT isozymes localized in mitochondria, plastids, nuclei, and the cytosol. Knowledge of the biochemical properties of each isozyme is central to understanding and manipulating one-carbon metabolism in plants. We heterologously expressed and purified three recombinant SHMTs from A. thaliana (AtSHMTs) putatively localized in mitochondria (two) and the cytosol (one). Their biochemical properties were characterized with respect to the impact of folate polyglutamylation on substrate saturation kinetics. The two mitochondrial AtSHMTs, but not the cytosolic one, had increased turnover rates at higher (>0.4ng/μL) enzyme concentrations in the presence of monoglutamylated folate substrates, but not in the presence of pentaglutamylated folate substrates. We found no experimental support for a change in oligomerization state over the range of enzyme concentration studied. Modeling of the enzyme structures presented features that may explain the activity differences between the mitochondrial and cytosolic isozymes.
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Details
- Title
- Folate polyglutamylation eliminates dependence of activity on enzyme concentration in mitochondrial serine hydroxymethyltransferases from Arabidopsis thaliana
- Creators
- Zhaoyang Wei - Institute of Biological Chemistry, Washington State University, Pullman, WA 99164, USAKehan Sun - Institute of Biological Chemistry, Washington State University, Pullman, WA 99164, USAFrancisco J Sandoval - Institute of Biological Chemistry, Washington State University, Pullman, WA 99164, USAJoanna M Cross - German Institute of Food Technologies, Prof.-von-Klitzing-Str. 7, D-49610 Quakenbrück, GermanyChristine Gordon - Pacific Lutheran University, Tacoma, WA 98447, USAChulHee Kang - Department of Chemistry, Washington State University, Pullman, WA 99164, USASanja Roje - Institute of Biological Chemistry, Washington State University, Pullman, WA 99164, USA
- Publication Details
- Archives of biochemistry and biophysics, Vol.536(1), pp.87-96
- Academic Unit
- Chemistry, Department of; Biological Chemistry, Institute of
- Publisher
- Elsevier Inc
- Identifiers
- 99900547706501842
- Language
- English
- Resource Type
- Journal article