title: A minimal hydrophobicity is needed to employ amphiphilic p(HPMA)-co-p(LMA) random copolymers in membrane research.
abstract: Because a polymer environment might be milder than a detergent micelle, amphiphilic polymers have attracted attention as alternatives to detergents in membrane biochemistry. The polymer poly[N-(2-hydroxypropyl)-methacrylamid] [p(HPMA)] has recently been modified with hydrophobic lauryl methacrylate (LMA) moieties, resulting in the synthesis of amphiphilic p(HPMA)-co-p(LMA) polymers. p(HPMA)-co-p(LMA) polymers with a LMA content of 5 or 15% have unstable hydrophobic cores. This, on one hand, promotes interactions of the hydrophobic LMA moieties with membranes, resulting in membrane rupture, but at the same time prevents formation of a hydrophobic, membrane mimetic environment that is sufficiently stable for the incorporation of transmembrane proteins. On the other hand, the p(HPMA)-co-p(LMA) polymer with a LMA content of 25% forms a stable hydrophobic core structure, which prevents hydrophobic interactions with membrane lipids but allows stable incorporation of membrane proteins. On the basis of our data, it becomes obvious that amphiphilic polymers have to have threshold hydrophobicities should an application in membrane protein research be anticipated.
authors.affiliation: Institut für Pharmazie und Biochemie, Johannes Gutenberg-Universität Mainz , Johann-Joachim-Becher-Weg 30, 55128 Mainz, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Stangl
authors.forename: Mirjam
authors.initials: M
authors.lastname: Hemmelmann
authors.forename: Mareli
authors.initials: M
authors.lastname: Allmeroth
authors.forename: Rudolf
authors.initials: R
authors.lastname: Zentel
authors.forename: Dirk
authors.initials: D
authors.lastname: Schneider
mesh_terms: D057927:Hydrophobic and Hydrophilic Interactions; D008689:Methacrylates / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*
chemical_list: D008689:Methacrylates; D011108:Polymers; C032802:hydroxypropyl methacrylate