Association studies to transporting proteins of fac-ReI(CO)3(pterin)(H2O) complex.
A new synthetic route to acquire the water soluble complex fac-ReI(CO)3(pterin)(H2O) was carried out in aqueous solution. The complex has been obtained with success via the fac-[ReI(CO)3(H2O)3]Cl precursor complex. ReI(CO)3(pterin)(H2O) has been found to bind strongly with bovine and human serum albumins (BSA and HSA) with intrinsic-binding constants, Kb, of 6.5 × 105M-1and 5.6 × 105M-1at 310 K, respectively. The interactions of serum albumins with ReI(CO)3(pterin)(H2O) were evaluated employing UV-vis fluorescence and absorption spectroscopy and circular dichroism. The results suggest that the serum albumins-ReI(CO)3(pterin)(H2O) interactions occurred in the domain IIA-binding pocket without loss of helical stability of the proteins. The comparison of the fluorescence quenching of BSA and HSA due to the binding to the Re(I) complex suggested that local interaction around the Trp 214 residue had taken place. The analysis of the thermodynamic parameters ΔG0, ΔH0, and ΔS0indicated that the hydrophobic interactions played a major role in both HSA-Re(I) and BSA-Re(I) association processes. All these experimental results suggest that these proteins can be considered as good carriers for transportation of ReI(CO)3(pterin)(H2O) complex. This is of significant importance in relation to the use of this Re(I) complex in several biomedical fields, such as photodynamic therapy and radiopharmacy.
INIFTA, UNLP, (CCT La Plata-CONICET), Diag. 113 y 64, C.C. 16, Suc. 4, B1906ZAA, La Plata, Argentina.
Fabricio
F
Ragone
INIFTA, UNLP, (CCT La Plata-CONICET), Diag. 113 y 64, C.C. 16, Suc. 4, B1906ZAA, La Plata, Argentina.
Héctor H Martínez
HH
Saavedra
INFIQC-CONICET, Dpto. de Fisicoquímica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000, Córdoba, Argentina.
Pablo F
PF
García
INIFTA, UNLP, (CCT La Plata-CONICET), Diag. 113 y 64, C.C. 16, Suc. 4, B1906ZAA, La Plata, Argentina.
Ezequiel
E
Wolcan
INFIQC-CONICET, Dpto. de Fisicoquímica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000, Córdoba, Argentina.
Gerardo A
GA
Argüello
INIFTA, UNLP, (CCT La Plata-CONICET), Diag. 113 y 64, C.C. 16, Suc. 4, B1906ZAA, La Plata, Argentina. gruiz@inifta.unlp.edu.ar.
Gustavo T
GT
Ruiz
D000818:Animals; D002417:Cattle; D006801:Humans; D008958:Models, Molecular; D009942:Organometallic Compounds / Q000737:chemistry* / Q000378:metabolism*; D000072756:Protein Conformation, alpha-Helical; D055550:Protein Stability; D011622:Pterins / Q000737:chemistry*; D012211:Rhenium / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000378:metabolism*; D012995:Solubility; D013057:Spectrum Analysis; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*
D009942:Organometallic Compounds; D011622:Pterins; D014867:Water; D012710:Serum Albumin, Bovine; D012211:Rhenium
Binding study; Circular dichroism; Fluorescence quenching; Rhenium(I) complex; Serum albumins; Thermodynamic parameters