MBE Advance Access published online on October 7, 2009
Molecular Biology and Evolution, doi:10.1093/molbev/msp241
Research Article |
The Cytophaga hutchinsonii ChTPSP: first characterized bifunctional TPS-TPP protein as putative ancestor of all eukaryotic trehalose biosynthesis proteins
1 Department of Molecular microbiology, VIB, Kasteelpark Arenberg 31, 3001. Heverlee Belgium
2 Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, K.U. Leuven, Kasteelpark Arenberg 31, B-3001. Heverlee Belgium
3 Bioinformatics Training and Service facility (BITS), VIB, Technologiepark 927, B-9052 Zwijnaarde, Belgium
Corresponding author: Patrick Van Dijck, VIB Department of Molecular Microbiology, K.U. Leuven, Laboratory of Molecular Cell Biology, K.U. Leuven, Kasteelpark Arenberg 31, B-3001 Leuven, Belgium, Email: Patrick.vandijck{at}mmbio.vib-kuleuven.be, Tel: +32 16321512, Fax: +32 16321979
Received for publication June 7, 2009. Revision received September 25, 2009. Accepted for publication October 1, 2009.
The most widely distributed pathway to synthesize trehalose in nature consists of two consecutive enzymatic reactions with a trehalose-6-P (T6P)-synthase (TPS) enzyme, producing the intermediate T6P, and a T6P-phosphatase (TPP) enzyme, which dephosphorylates T6P to produce trehalose and inorganic phosphate. In plants these enzymes are called Class I and Class II proteins respectively with some class I proteins being active enzymes. The Class II proteins possess both TPS and TPP consensus regions, but appear to have lost enzymatic activity during evolution. Plants also contain an extra group of enzymes of small protein size of which some members have been characterized as functional TPPs. These Class III proteins have less sequence similarity with the Class I and Class II proteins. Here, we characterize for the first time, by using biochemical analysis and yeast growth complementation assays, the existence of a natural TPS-TPP bifunctional enzyme, found in the bacterial species Cytophaga hutchinsonii. Through phylogenetic analysis we show that prokaryotic genes such as ChTPSP might be the ancestor of the eukaryotic trehalose biosynthesis genes. Second, we show that plants have recruited during evolution, possibly by horizontal transfer from bacteria such as Rhodopherax ferrireducens, a new type of small protein, encoding TPP activity, which have been named Class III proteins. RfTPP has very high TPP activity upon expression in yeast. Finally, we demonstrate that TPS gene duplication, the recruitment of the class III enzymes and recruitment of a N-terminal regulatory element, that regulates the class I enzyme activity in higher plants, were initiated very early in eukaryan evolution as the three classes of trehalose biosynthesis genes are already present in the alga Ostreococcus tauri.
Key Words: trehalose • TPS • TPP • Arabidopsis thaliana • plant evolution
* J.W. is currently employed at Pronota N.V., Technologiepark 4, B-9052 Zwijnaarde, Belgium