Blue Copper Proteins: A rigid machine for efficient electron transfer, a flexible device for metal uptake.
Blue Copper Proteins (BCPs) are small and generally soluble copper-containing proteins which participate in monoelectron transfer processes in biological systems. An overview of their electronic and tertiary structure is detailed here. The well-established entatic/rack-induced mechanism is explained by comparing thermodynamic parameters between the folded (tense) and the unfolded (relaxed) forms of the BCP rusticyanin. Recently, NMR solution data have shown that the active sites of BCPs in absence of the metal ion, i.e. in the apoforms, are flexible in the micro-to-second timescale. The rigidity proposed by the entatic/rack-induced mechanism is an imperative for the holoprotein to perform electron transfer; while the flexibility of the apocupredoxin is necessary to uptake the metal ion from the metallochaperones. These apparently contradictory requirements are discussed in the present work. Finally, the role of azurin and some peptides derived from it in anticancer therapy are also described.
Department of Inorganic Chemistry, Faculty of Chemistry, University of Murcia, Campus Universitario de Espinardo, 30100 Murcia, Spain.
Sergio Alejo
SA
Pérez-Henarejos
Bioarray SL, Alicante, Parque Científico de la UMH, Avda Universidad s/n, 03202 Elche, Alicante, Spain.
Luis A
LA
Alcaraz
Department of Inorganic Chemistry, Faculty of Chemistry, University of Murcia, Campus Universitario de Espinardo, 30100 Murcia, Spain. Electronic address: adonaire@um.es.
Antonio
A
Donaire
D000818:Animals; D001693:Biological Transport, Active / Q000502:physiology; D003300:Copper / Q000737:chemistry* / Q000378:metabolism*; D004579:Electron Transport / Q000502:physiology; D006801:Humans; D008667:Metalloproteins / Q000737:chemistry* / Q000378:metabolism*; D058767:Protein Unfolding
D008667:Metalloproteins; D003300:Copper
Azurin; Blue Copper Proteins; Cancer therapy; Rack/entatic; Rusticyanin