title: Changes in protein conformation and surface hydrophobicity upon peroxidase-catalyzed cross-linking of apo-α-lactalbumin.
abstract: In this study, we explore the effect of peroxidase-catalyzed cross-linking on the molecular conformation of apo-α-lactalbumin (apo-α-LA) and the resulting changes in protein surface hydrophobicity. In studying conformational changes, we distinguish between early stages of the reaction ("partial cross-linking"), in which only protein oligomers (10(6) Da > Mw ≥ 10(4) Da) are formed, and a later stage ("full cross-linking"), in which larger protein particles (Mw ≥ 10(6) Da) are formed. Partial cross-linking induces a moderate loss of α-helical content. Surprisingly, further cross-linking leads to a partial return of α-helices that are lost upon early cross-linking. At the same time, for partially and fully cross-linked apo-α-LA, almost all tertiary structure is lost. The protein surface hydrophobicity first increases for partial cross-linking, but then decreases again at full cross-linking. Our results highlight the subtle changes in protein conformation and surface hydrophobicity of apo-α-LA upon peroxidase-catalyzed cross-linking.
authors.affiliation: Laboratory of Physical Chemistry and Colloid Science, Wageningen University , P.O. Box 8038, 6700 EK Wageningen, The Netherlands.
authors.forename: Yunus
authors.initials: Y
authors.lastname: Saricay
authors.forename: Peter A
authors.initials: PA
authors.lastname: Wierenga
authors.forename: Renko
authors.initials: R
authors.lastname: de Vries
mesh_terms: D000818:Animals; D001059:Apoproteins / Q000737:chemistry*; D002384:Catalysis; D002417:Cattle; D002942:Circular Dichroism; D006735:Horseradish Peroxidase / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D007768:Lactalbumin / Q000737:chemistry*; D011487:Protein Conformation
chemical_list: D001059:Apoproteins; C041966:apo-alpha-lactalbumin; D007768:Lactalbumin; D006735:Horseradish Peroxidase
keywords: enzymatic cross-linking; horseradish peroxidase; protein nanoparticles; structural transition; surface hydrophobicity; α-lactalbumin