STRUCTURAL AND DYNAMIC CHARACTERIZATION OF PfGRASP ISOFORMS FROM PLASMODIUM FALCIPARUM USING COARSE-GRAINED MOLECULAR DYNAMICS

Golgi Reassembly and Stacking Proteins (GRASPs) are peripheral membrane proteins involved in Golgi organization and unconventional protein secretion (UPS). Previous studies from our group have shown that members of this family display features typically associated with intrinsically disordered proteins (IDPs), including molten-globule-like behavior and liquid–liquid phase separation (LLPS). Plasmodium falciparum, the causative agent of malaria, encodes two GRASP isoforms. PfGRASP1 and PfGRASP2 arise from alternative splicing and differ in their membrane-anchoring mechanisms. Despite their biological relevance, the structural properties of these proteins remain poorly understood. Preliminary experimental results showed successful expression and purification of PfGRASP2, as confirmed by liquid chromatography and SDS–PAGE. Two distinct chromatographic peaks were observed, and dynamic light scattering measurements revealed hydrodynamic radii of approximately 6.7 and 11 nm for the corresponding fractions. These results may indicate the presence of different oligomeric or conformational states of PfGRASP2. Circular dichroism measurements were also performed to investigate its structural properties and thermal stability. In parallel, this project aims to characterize the structural and dynamic behavior of full-length PfGRASP1 and PfGRASP2 by means of coarse-grained molecular dynamics simulations using the OpenAWSEM force field. The resulting trajectories will be analyzed in terms of radius of gyration, root-mean-square deviation (RMSD), root-mean-square fluctuation (RMSF), and free-energy landscapes obtained from PMF/WHAM calculations. These analyses will allow a comparative assessment of the conformational properties of the two isoforms and may provide new insights into the relationship between intrinsic disorder, membrane anchoring, and functional diversification in GRASP proteins from P. falciparum.