INIBIOLP   05426
INSTITUTO DE INVESTIGACIONES BIOQUIMICAS DE LA PLATA "PROF. DR. RODOLFO R. BRENNER"
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Protein-ligand interaction and structure refinement of novel nematodeFABP, As-p18
Autor/es:
IBAÑEZ SHIMABUKURO M.; M. FLORENCIA REY BURUSCO; ALAN COOPER; MALCOLM W. KENNEDY; BETINA CÓRSICO; BRIAN O. SMITH
Lugar:
San Javier, Tucumán
Reunión:
Congreso; XLI Reunión Anual de la Sociedad Argentina de Biofísica; 2012
Resumen:
As-p18 is a developmentally regulated fatty acid binding protein (FABP) found in the perivitelline fluid surrounding the infective larva (L3) of Ascaris suum within the egg. Once fully developed, the L3 remains quiescent, persisting for several years until ingestion by the host, but little is known about the biochemical and physiological basis for such long term survival. One of the most abundant protein components in the fluid that surrounds the developing larva is the nemFABP, As-p18, which may be involved in the prolonged viability of the infective Ascaris eggs1. Here we present the structure of As-p18 in solution complexed with oleate, emphasising the refinement process. The use of residual dipolar couplings (RDCs) in structure calculations considerably improved the definition of NMR-derived structures, and resulted in better agreement with the crystallographic structure2. The backbone amide protons involved in hydrogen bonds were identified by their rate of exchange with deuterium in the solvent, giving rise to 108 hydrogen bond restraints, also improving the quality of the NMR ensemble. NMR titration experiments showed only one ligand binding site. An analysis of the protein-ligand interactions derived from isotope-filtered experiments employing a variety of labelling schemes for the protein-ligand complexes, enabled mapping of amino acids in proximity with the ligand. This work provides a structural characterisation of As-p18 that may contribute to the understanding of this protein´s role in A. suum infective eggs, and more generally to the unique features of nematode FABPs.