DNA interaction with human serum albumin studied by affinity capillary electrophoresis and FTIR spectroscopy.
The question addressed in this study is how does the protein-DNA complexation affect the structure and dynamics of DNA and protein in aqueous solution. We examined the interaction of calf-thymus DNA with human serum albumin (HSA) in aqueous solution at physiological conditions, using constant DNA concentration of 12.5 mM (phosphate) and various HSA contents 0.25 to 2% or 0.04 to 0.3 mM. Affinity capillary electrophoresis and FTIR spectroscopic methods were used to determine the protein binding mode, the association constant, sequence preference, and the biopolymer secondary structural changes in the HSA-DNA complexes. Spectroscopic evidence showed two types of HSA-DNA complexes with strong binding of K(1) = 4.5 x 10(5) M(-1) and weak binding of K(2) = 6.10 x 10(4) M(-1). The two major binding sites were located on the G-C bases and the backbone PO(2) group. The protein-DNA interaction stabilizes the HSA secondary structure. A minor alteration of B-DNA structure was observed, while no major protein conformational changes occurred.
Malonga
H
H
Department of Chemistry-Biology, University of Québec at Trois-Rivières, Canada.
Neault
J F
JF
Arakawa
H
H
Tajmir-Riahi
H A
HA
D000818:Animals; D001665:Binding Sites; D002417:Cattle; D004247:DNA / Q000737:chemistry*; D019075:Electrophoresis, Capillary; D006801:Humans; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D011487:Protein Conformation; D012709:Serum Albumin / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared
D012709:Serum Albumin; D004247:DNA; C427203:calf thymus DNA