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New laser fluorenscence methods for the study of protein/lipid interactions


Research objectives and content
The functional role that lipid-peptide interactions play in a wide range of biological processes is acquiring growing experimental support. Nevertheless, detailed knowledge of the basic molecular mechanisms underlying these interactions is lacking. The study of model systems consisting of peptides interacting with lipid bilayers is proving a valuable contribution to a better understanding of these mechanisms. The goal of the present Project is to investigate the molecular details of lipid-peptide interaction, especially with respect to membrane insertion. The peptides selected are the a-melanotropin hormone, essential in regulating skin pigmentation, and two analogues, possessing more potent biological activity. The affinity of these peptides for lipid vesicles containing different types of phospholipids and cholesterol will be investigated in a comparative way using fluorescence spectroscopy and infrared absorption by Fourier transform. A correlation between the different activity of the peptides and the mode of the interaction with the membrane will be proposed. The particular methodologies regarding fluorescence will be quantum yields, lifetimes, steady-state and time-resolved fluorescence anisotropy measurements and, especially, resonance energy transfer, using the single tryptophan of the peptides as energy donor and the new fluorescent octadecapentaenoic acid t-COPA as acceptor. Since the advantageous properties of this new probe, one of the aim of the Project is to develop a detailed operational method for the use of t-COPA in the research of peptide(protein)-lipid interaction. Training content (objective, benefit and expected impact)
This project offers a large number of training opportunities for the applicant. On the conceptual side, a good knowledge of molecular electronic spectroscopy, theories on energy transfer in two-dimensions, lipid-peptide interaction models would be required for the interpretation of the planned experiments. On the instrumental side, the applicant would be exposed to a large variety of instrumentation of fairly, general use in time-resolved spectroscopy within the subnanosecond time-range. There are very few researchers in the country of origin of the applicant who are familiar with these fields.
Links with industry / industrial relevance ( 22 )
The experimental methods derived from fluorescence spectroscopy have the right sensitivity and versatility to be applied to biosystems under physiological conditions. These advantages are used by those laboratories -academic and industrial- involved in the research and development of new methods of investigation and diagnostics for biomedical field. The research describes in this project is relevant to that effort.

Funding Scheme

RGI - Research grants (individual fellowships)


Avl. Rovisco Pais
1049-001 Lisboa