The levansucrase puzzle: how to combine structure and
biochemistry to understand the biological function
Ivan Polsinelli1, Rosanna Caliandro1,
Marco Salomone-Stagni1, Nicola Demitri2, Martin Rejzek3,
Robert A. Field3, Stefano Benini1,*
1 Bioorganic Chemistry
and Bio-Crystallography laboratory (B2Cl), Faculty of Science and
Technology, Free University of Bolzano, Piazza Università 5, 39100
Bolzano, Italy
2 Elettra-Sincrotrone
Trieste, S.S. 14 Km 163.5 in Area Science Park, Basovizza, Trieste 34149, Italy
3 Department of
Biological Chemistry, John Innes Centre, Norwich Research Park, Norwich,
NR47UH, United Kingdom
* corresponding author: stefano.benini@unibz.it
The Gram-negative
bacterium Erwinia amylovora is the etiological agent of fire
blight, a devastating disease which affects Rosaceae. Activity of
levansucrase has been correlated with the virulence of E. amylovora. E.
amylovora levansucrase
defective mutants, showed retarded development of necrotic symptoms on pear
seedlings inoculated with the mutated strains [1]. The plant pathogen E.
amylovora is related to the epiphytic bacterium Erwinia tasmaniensis [2, 3].
To understand the role of
this enzyme in the two bacteria, the levansucrase from E. tasmaniensis
(EtLsc) has been compared with the homologous enzyme from E. amylovora
(EaLsc) [4]. The enzymatic activity was characterized by High Performance Anion Exchange Chromatography coupled
with Pulsed Amperometric Detector (HPAEC-PAD). The comparison of the
products profile highlights an increased efficiency of EtLsc than EaLsc. The
crystal structure of EtLsc reveals structural peculiarities causing the
different product profiles of the two homologues.
Based on our results, we
propose that the role of this enzyme in the life cycle of the two bacteria is
most likely related to survival, rather than linked to the virulence of the
plant pathogen E. amylovora [5].
1. Geier, G., Geider, K., 1993.
Characterization and influence on virulence of the levansucrase gene from the
fireblight pathogen Erwinia-amylovora. Physiological and Molecular
Plant Pathology 42, pp. 387-404.
2. Geider, K., Auling, G., Du, Z., Jakovljevic, V., Jock,
S., Volksch, B., 2006. Erwinia tasmaniensis sp. nov., a
non-phytopathogenic bacterium from apple and pear trees. Int. J. Syst. Evol.
Microbiol. 56, pp. 2937-2943.
3. Borruso, L., Salomone-Stagni, M., Polsinelli, I.,
Schmitt, A.O., Benini, S., 2017. Conservation of Erwinia amylovora pathogenicity-relevant genes among Erwinia
genomes. Arch. Microbiol. 199, pp. 1335-1344.
4. Caputi, L., Nepogodiev, S.A.,
Malnoy, M., Rejzek, M., Field, R.A., Benini, S., 2013. Biomolecular
characterization of the levansucrase of Erwinia amylovora, a promising
biocatalyst for the synthesis of fructooligosaccharides. J. Agric. Food
Chem. 61, pp. 12265-12273.
5. Polsinelli, I., Caliandro, R.,
Salomone-Stagni, M., Demitri, N., Rejzek, M., Field, R.A., Benini, S., 2019.
Comparison of the Levansucrase from the epiphyte Erwinia tasmaniensis vs
its homologue from the phytopathogen Erwinia amylovora. Int. J. Biol.
Macromol. 127, pp. 496-501.