title: Modeling of bovine type-I collagen fibrils: interaction with pickling and retanning agents.
abstract: Bovine Type I collagen was investigated, building on a large scale computer model of a collagen fibril in water, and focusing on two stages of the leather manufacturing process. The effects of different salts (NaCl, CaCl(2), and Na(2)SO(4)) on the swelling behavior of collagen at low pH (the pickling process) were studied. The salts suppress the swelling of the fibrils at low pH and we find specific stabilizing influences for CaCl(2) and Na(2)SO(4), due to weak Ca(2+)/Cl(-) and strong SO(4) (2-)/lysine/arginine interactions, respectively. Using state-of-the-art sampling techniques, such as the metadynamics algorithm, to allow an efficient exploration of configuration space, we were able to investigate the effect of polyacrylate and poly(methyl acrylate) - two polymeric retanning agents - on the fibril. Both polymers interact with the ammonium groups on the surface, but polyacrylate shows significantly stronger interactions. We suggest that it is this stronger interaction that contributes to the reduced suitability of PAA as a tanning agent.
authors.affiliation: BASF Aktiengesellschaft, Polymer Physics, Carl-Bosch Strasse 38, 67056 Ludwigshafen, Germany.
authors.forename: Rosa E
authors.initials: RE
authors.lastname: Bulo
authors.forename: Lorenz
authors.initials: L
authors.lastname: Siggel
authors.forename: Ferenc
authors.initials: F
authors.lastname: Molnar
authors.forename: Horst
authors.initials: H
authors.lastname: Weiss
mesh_terms: D000465:Algorithms; D000818:Animals; D002122:Calcium Chloride / Q000378:metabolism / Q000494:pharmacology; D002417:Cattle; D024042:Collagen Type I / Q000187:drug effects / Q000378:metabolism*; D003198:Computer Simulation; D005404:Fixatives / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008954:Models, Biological; D011109:Polymethacrylic Acids / Q000378:metabolism / Q000494:pharmacology; D012965:Sodium Chloride / Q000378:metabolism / Q000494:pharmacology; D013431:Sulfates / Q000378:metabolism / Q000494:pharmacology; D013633:Tanning / Q000379:methods*
chemical_list: D024042:Collagen Type I; D005404:Fixatives; D011109:Polymethacrylic Acids; D013431:Sulfates; C012036:sodium sulfate; D012965:Sodium Chloride; D002122:Calcium Chloride