On the Roles of Wheat Endosperm ADP-Glucose Pyrophosphorylase Subunits

FERRERO, DANISA M. L.; FALASCHETTI, CHRISTINE A.; BALLICORA*, MIGUEL A.; ASENCION DIEZ, MATIAS D.; PIATTONI, CLAUDIA V.; KUHN, MISTY L.; IGLESIAS*, ALBERTO A.

Frontiers in Plant Science

Frontiers

Lugar: Lussane; Año: 2018 vol. 9

The ADP-glucose pyrophosphorylase from wheat endosperm controls starch synthesisin seeds and has unique regulatory properties compared to others from this family.It comprises two types of subunits, but despite its importance little is knownabout their roles. Here, we synthesized de novo the wheat endosperm ADP-glucosepyrophosphorylase small (S) and large (L) subunit genes, heterologously expressedthem in Escherichia coli, and kinetically characterized the recombinant proteins. Tounderstand their distinct roles, we co-expressed them with well characterized subunitsfrom the potato tuber enzyme to obtain hybrids with one S subunit from one source andan L subunit from the other. After kinetic analyses of these hybrids, we concluded thatthe unusual insensitivity to activation of the wheat endosperm enzyme is caused by apre-activation of the L subunit. In addition, the heat stability and sensitivity to phosphateare given by the S subunit.