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.