Imobilização da proteína fusionada MBP-Gal-1 sobre PPB eletropolimerizado

Galectins are known as glycan binding proteins (GBP) which play important roles in a variety of processes from immunoregulatory activities to microbial killing. The role of galectin 1 (Gal-1) in tumor progression and proliferation, angiogenesis, resistance to drugs and masking against recognition by the immune system have been studied [1]. In this context, the use of biosensors is important as an analytical tool for identifying and quantifying a detectable signal. There is a great interest in new methods for immobilizing biomolecules, onto a surface, allowing maximum retention of activity. Genetic engineering can be employed to develop biosensors and introduce functional groups into biological molecules giving rise to the chimeric protein-based sensors for ligand binding [2]. Previous work reported that the Maltose Binding Protein (MBP) tag domain interacts strongly with N-(3-pyrrol- 1-ylpropyl)-4,4′-bipyridinium electropolymerized film (PPB) [3]. In this work, we described the purification and expression of a MBP-Gal-1 fused protein and the electrochemical and piezoelectric behavior of this biomolecule, comparing to its wild type form, Gal-1. Impedimetric measurements have showed resistance changes when MBP-Gal-1 was immobilized onto PPB film. It was also observed changing in resistance when lactose was added on MBP-Gal-1 and its wild type form, Gal-1. These results indicate that the MBP-Gal-1 immobilized on PPB films produces changes in resistance more consistent than the wild type. The obtained results on bare electrodes depend on the material, since Gal-1 has cysteine groups that bound on gold. Results suggest that this system could be used as a biosensor to analyses lactose. Moreover, this device could be a starting point to construct an immunosensor to detect anti-galectin.