Structure-Function of β -Galactosidase in Inclusion Bodies.

FLORES, SANDRA SOLEDAD; SANCHEZ, JULIETA; PERILLO, MARÍA ANGÉLICA

San Miguel de Tucuman

Congreso; III LAFeBS IX Ibero American Congress of Biophysics XLV SAB. Tucuman, Argentina; 2016

Sociedad Argentina de Biofisica

From the first studies of beta galactosidase (B-gal) it was established that the active form of the enzyme is a homotetramer but has residual activity as a dimer. In later studies in our laboratory we proposed that the enzyme could present higher oligomerization states when the enzyme interacts with liposomes interfaces and thus safeguard its stability against aggressive environmental conditions like higher temperature, pH and proteolysis. Now we produce in our laboratory B-gal structured in inclusion bodies (IB). We demonstrated that the enzyme still active in this condition. Production of IB was carried out under conditions that favor the specific activity of B-gal (Temperature induction of expression condition, Ti= 30°C instead of Ti= 37° C). Successive washings of IB proved enzyme IB-desorption with different protein quality (variable specific activity). An heterogeneous structural quality within the aggregate was previously reported for other proteins structured in IB. Our studies also suggest that the enzyme activity measured in IB samples comes mainly from the enzyme that desorbed from these supramolecular structures during the catalysis. On the other hand, the analysis of the B-gal fluorescence emission spectra showed that lambda max of the enzyme that desorbed from IB change towards minor values than the soluble enzyme. Suggesting that it may be still in an oligomeric state or exhibit a new soluble protein conformation.