Functional characterization of Legionella pneumophila Cu + transport ATPase. The activation by Cu + and ATP.

Autor: Placenti MA; Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Química Biológica, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Química y Fisicoquímica Biológicas, Buenos Aires, Argentina., Roman EA; Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Química y Fisicoquímica Biológicas, Buenos Aires, Argentina; Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Biológica, Buenos Aires, Argentina., González Flecha FL; Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Química Biológica, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Química y Fisicoquímica Biológicas, Buenos Aires, Argentina. Electronic address: lgf@qb.ffyb.uba.ar., González-Lebrero RM; Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Química Biológica, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Química y Fisicoquímica Biológicas, Buenos Aires, Argentina. Electronic address: lolo@qb.ffyb.uba.ar.
Jazyk: angličtina
Zdroj: Biochimica et biophysica acta. Biomembranes [Biochim Biophys Acta Biomembr] 2022 Feb 01; Vol. 1864 (2), pp. 183822. Date of Electronic Publication: 2021 Nov 24.
DOI: 10.1016/j.bbamem.2021.183822
Abstrakt: Cu + -ATPases are integral membrane proteins belonging to the IB subfamily of the P-type ATPases that couple Cu + transport to the hydrolysis of ATP. As some structural and functional particularities arise for Cu + -ATPases, several authors suggest that some of the reaction steps of the Albers-Post model postulated for other P-ATPases may be different. In this work we describe a functional characterization of Legionella pneumophila Cu + -ATPase (LpCopA), the first P IB -ATPase whose structure was determined by X-ray crystallography. Cu + -ATPase activity of the enzyme presents a maximum at ∼37 °C and pH 6.6-6.8. Phospholipids enhance LpCopA Cu + -ATPase activity in a non-essential mode where optimal activity is achieved at an asolectin molar fraction of 0.15 and an amphiphile-protein ratio of ~30,000. As described for other P-ATPases, Mg 2+ acts as an essential activator. Furthermore, Cu + -ATPase activity dependence on [Cu + ] and [ATP] can both be described by a sum of two hyperbolic functions. Based on that, and the [Cu + ] and [ATP] dependencies of the best fitting parameters of the hyperbolae pointed above, we propose a minimal reaction scheme for the catalytic mechanism that shares the basic reaction steps of the Albers-Post model for P-type ATPases. The reaction scheme postulated contemplates two different binding affinities for a single ATP (apparent affinities of 0.66 and 550 μM at [Cu + ] → ∞) and binding of at least 2 Cu + with different affinities as well (apparent affinities of 1.4 and 102.5 μM at [ATP] → ∞).
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Databáze: MEDLINE
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