title: Dendrimers bind human serum albumin.
abstract: Dendrimers are synthetic, highly branched, spherical macromolecules with nanometer dimensions and potential applications in DNA and drug delivery systems. Human serum albumin (HSA) is a major transporter for delivering several endogenous compounds and drugs in vivo. The aim of this study was to examine the interaction of human serum albumin with several dendrimers such as mPEG-PAMAM (G3), mPEG-PAMAM (G4), and PAMAM (G4) at physiological conditions, using constant protein concentration and various dendrimer compositions. FTIR, UV-visible, CD, and fluorescence spectroscopic methods were used to analyze macromolecule binding mode, the binding constant and the effects of dendrimers complexation on HSA stability and conformation. Structural analysis showed that dendrimers bind HSA via polypeptide polar groups (hydrophilic) with number of bound polymer (n) 1.08 (mPEG-PAMAM-G3), 1.50 (mPEG-PAMAM-G4), and 0.96 (PAMAM-G4). The overall binding constants estimated were of KmPEG-G3=1.3 (+/-0.2)x10(4) M(-1), KmPEG-G4=2.2 (+/-0.4)x10(4) M(-1), and KPAMAM-G4=2.6 (+/-0.5)x10(4) M(-1). HSA conformation was altered by dendrimers with a major reduction of alpha-helix and increase in random coil and turn structures suggesting a partial protein unfolding.
authors.affiliation: Département de Chimie-Biologie, Université du Quebec à Trois-Rivières, C. P. 500, Trois-Rivières, Québec, G9A 5H7, Canada.
authors.forename: E
authors.initials: E
authors.lastname: Froehlich
authors.forename: J S
authors.initials: JS
authors.lastname: Mandeville
authors.forename: C J
authors.initials: CJ
authors.lastname: Jennings
authors.forename: R
authors.initials: R
authors.lastname: Sedaghat-Herati
authors.forename: H A
authors.initials: HA
authors.lastname: Tajmir-Riahi
mesh_terms: D002942:Circular Dichroism; D050091:Dendrimers / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D008958:Models, Molecular; D011485:Protein Binding; D055550:Protein Stability; D017433:Protein Structure, Secondary; D012709:Serum Albumin / Q000737:chemistry / Q000378:metabolism*; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D014867:Water / Q000737:chemistry
chemical_list: D050091:Dendrimers; D012709:Serum Albumin; D014867:Water