INVESTIGADORES
ROSSI juan pablo Francisco
congresos y reuniones científicas
Título:
Conformational changes by ATP binding in the plasma membrane calcium pump
Autor/es:
SAFFIOTI NICOLÁS, FERREIRA-GOMES MARIELA, ROSSI JUAN PABLO F. C. AND MANGIALAVORI IRENE C.
Lugar:
Tucumán
Reunión:
Congreso; XLI Reunión Anual de la Sociedad Argentina de Biofísica (SAB).; 2012
Institución organizadora:
Sociedad Argentina de Biofísica
Resumen:
Conformational changes by ATP binding in the plasma membrane calcium
pump. Saffioti Nicolás, Ferreira-Gomes Mariela, Rossi Juan
Pablo F. C. and Mangialavori Irene C. Libro de Resúmenes: Pag 105.
Plasma
membrane calcium pump (PMCA) is a P-ATPase that transports Ca2+
against the electrochemical gradient from the cytoplasm to the outer cellular
medium. The principal modulator of PMCA is calmodulin which increase its Ca2+
affinity and the maximum transport rate. The reaction cycle of the pump can be
described by the E1-E2 model. The first step is the Ca2+ binding to
the protein, drawing it to the E1 conformation. The ATP binding and the later
autophosphorylation elicit PMCA to E1P. In the next step the pump
reaches the E2P conformation, which allows the liberation of Ca2+ to
the cytoplasm. However it has been described that besides the catalytic role of
ATP; there is another binding site for the nucleotide with a regulatory role
associated with the E2 conformation. The aim of this work is to
study the ATP binding to purified PMCA and the associated conformational
changes, using the fluorescent analogue TNPATP. We also tested the
conformational changes associated with the presence of calmodulin. Our results
show that: (1) the TNP-ATP binds to the PMCA (2) The environment of the ATP
binding domain changes in the different conformations of the PMCA. (3) The PMCA
affinity for the TNP-ATP depends on the PMCA conformation (4) The PMCA affinity
for TNP-ATP is much lower in E2 conformation than in E1,
suggesting the existence of an ATP low-affinity binding site(s).
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Suzuki, H., Kubota, T. ,Kubo ,K. ,Kanazawa,
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