INVESTIGADORES
CHEHIN Rosana Nieves
congresos y reuniones científicas
Título:
FTIR studies on the interaction between glyceraldehyde-3-phosphate dehydrogenase and lipid bilayers
Autor/es:
AVILA CL; MORERO, R.D; CHEHÍN RN
Lugar:
Buenos Aires- Argentina
Reunión:
Workshop; International Workshop on Infrared Spectroscopy Applied to Biological and Biomimetic Systems: From the Isolated Molecule to the Cell; 2007
Resumen:
Cell membrane fusion is an essential requirement due to its leading role in crucial events of life, such as: membrane trafficking, myotube formation, secretory exocytosis, fertilization and virus infection. Lipids membranes do not fuse spontaneously and thus, the process requires energy and “catalyzers” which help to overcome barriers that maintain the membrane integrity. The best studied “membrane fusion catalyzers” are the divalent cations, like calcium. However, Protein-mediated membrane fusion was extensively studied and the best characterized systems are those involving viral glycoproteins mediating virus-induced cell fusion. Previous studies from our laboratory have shown that the fusion of phospholipid vesicles induced by GAPDH occurs in the absence of calcium and the process is highly dependent upon the pH. This fusogenic ability of GAPDH in vitro was also demonstrated in vivo. Computational results from our group using the classical Poisson-Boltzmann theory, demonstrated the electrostatic forces drive the protein membrane binding process. Moreover, structure and charge distribution studies performed on GAPDH showed a high positive electrostatic field arising from a deep crevice facing the membrane. However, our theoretical approaches could reveal neither the changes induced in the bilayer organization nor changes in the protein structure upon the protein-membrane binding. The FTIR technique is known to be a versatile and powerful tool to investigate changes that occur at different levels of the lipid bilayer, i.e, hydrophobic, interfacial and polar regions. In this work we use FTIR spectroscopy to study the GAPDH-liposome system in order to gain information about the protein-membrane binding features. In this way, careful studies on the polar, interfacial and hydrophobic region of the membrane were carried out. The obtained results together with electrostatic calculations shed light on the molecular mechanisms which are driving the membrane fusion process. Understanding the molecular events that occur in cell membranes upon binding of fusogenic proteins represent an intriguing challenge and spectroscopic techniques combined with bioinformatics showed to be a powerful tool in this area.