Background:
The O. tesota lectin PF2 is a tetrameric protein with subunits of 33 kDa that recognizes only complex carbohydrates, resistant to proteolytic enzymes and has insecticidal activity against Phaseolus beans pest.
Objective:
To explore PF2 lectin features at different protein structural levels and to evaluate the effect of temperature and
pH on its functionality and conformational stability.
Methods:
PF2 lectin was purified by affinity chromatography. Its primary structure was resolved by mass spectrometry and
analyzed by bioinformatic tools, including its tertiary structure homology modeling. The effect of temperature and pH on its
conformational traits and stability was addressed by dynamic light scattering, circular dichroism, and intrinsic fluorescence.
The hemagglutinating activity was evaluated using a suspension of peripheral blood erythrocytes.
Results:
The proposed PF2 folding comprises a high content of beta sheets. At pH 7 and 25 °C, the hydrodynamic diameter
(Dh) was found to be 12.3 nm which corresponds to the oligomeric native state of PF2 lectin. Dh increased under the other
evaluated pH and temperature conditions, suggesting protein aggregation. At basic pH, PF2 exhibited low conformational
stability. The native PF2 (pH 7) retained its full hemagglutinating activity up to 45 °C and exhibited one transition state with
a melting temperature of 76.8 °C.
Conclusion:
PF2 showed distinctive characteristics found in legume lectins. The pH influences the functionality and conformational stability of the protein. PF2 lectin displayed a relatively narrow thermostability to the loss of secondary structure and hemagglutinating activity.
Comparative Assessment of Tubular Ceramic, Spiral Wound, and Hollow Fiber Membrane Microfiltration Module Systems for Milk Protein Fractionation
