INVESTIGADORES
GOMEZ CASATI Diego Fabian
congresos y reuniones científicas
Título:
The S328-E330 and N338-W340 residues in D2 region are involved in the modulation of the activity of starch synthase III from A. thaliana.
Autor/es:
WAYLLACE, N. Z.; VALDEZ, H.; DIEGO FABIAN GOMEZ CASATI; BUSI, M. V.
Lugar:
Salta
Reunión:
Congreso; 3rd Latin American Protein Society; 2010
Institución organizadora:
LAPS
Resumen:
Starch synthase III from Arabidopsis thaliana contains an
N-terminal region, including three in-tandem starch-binding domains (SBD, named
D123), followed by a C-terminal catalytic domain (CD). We had reported
previously that SBDs are involved in the regulation of starch synthase III
function and recently, we demonstrated protein interaction between both
domains, showing that the amino acids in 316-344 and 495-535 regions in D2 and
D3 domains respectively, but not the individual SBDs, are involved in interaction
with catalytic domain (1,2). In this work, we used bioinformatic tools, scanning-Ala
assays, pull down and kinetic activity measurements in order to determine which
residues belonging to the D23 region are involved in the interaction with the
CD. By SDM, we generate a battery of Ala-modified D23 proteins between aminoacids
316-344, and the interaction with the CD was evaluated using pull down assays. Results
showed that S328-E330 and N338-W340 residues lost the ability to interact with
the CD. When these residues were changed by Ala in the full
length SSIII protein, the kinetic parameters were similar to that obtained for the
D3-CD truncated enzyme. The results presented here indicate that the
interaction of the N-terminal SBDs, particularly the 316-344 and 495-535 loops
regions, with the catalytic domains, are important in the modulation of SSIII
activity, and suggest that the S328-E330 and N338-W340 residues are involved in
this process.
References:
1- Valdez, H.A.; Busi, M.V.; Wayllace, N.Z.; Parisi, G.; Ugalde,
R.A. and Gomez-Casati, D.F. (2008) Biochemistry
47, 3026-3032.
2- Wayllace, N.Z.; Valdez, H.A.; Ugalde, R.A.; Busi, M.V. and
Gomez-Casati, D.F (2010). FEBS J 277, 428-440.
Acknowledgments: PIP CONICET 112-200801-00237 y
PROG07F/2 UNSAM