title: Partially reversible adsorption of annexin A1 on POPC/POPS bilayers investigated by QCM measurements, SFM, and DMC simulations.
abstract: The kinetics of annexin A1 binding to solid-supported lipid bilayers consisting of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC)/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoserine (POPS; 4:1) has been investigated as a function of the calcium ion concentration in the bulk phase. Quartz crystal microbalance measurements in conjunction with scanning force microscopy, fluorescence microscopy, and computer simulations indicate that at a given Ca2+ concentration annexin A1 adsorbs irreversibly on membrane domains enriched in POPS. By contrast, annexin A1 adsorbs reversibly on the POPC-enriched phase, which is composed of single POPS molecules embedded within a POPC matrix. The overall area occupied by the POPS-enriched phase is controlled by the CaCl2 concentration. Monte Carlo simulations suggest that the area of the POPS-enriched phase increases by a factor of 7 when the Ca2+ concentration is changed from 0.01 to 1 mM.
authors.affiliation: Institut für Analytische Chemie, Chemo- und Biosensorik, Universität Regensburg, 93040 Regensburg, Germany.
authors.forename: Katja
authors.initials: K
authors.lastname: Kastl
authors.forename: Manuela
authors.initials: M
authors.lastname: Menke
authors.forename: Eike
authors.initials: E
authors.lastname: Lüthgens
authors.forename: Simon
authors.initials: S
authors.lastname: Faiss
authors.forename: Volker
authors.initials: V
authors.lastname: Gerke
authors.forename: Andreas
authors.initials: A
authors.lastname: Janshoff
authors.forename: Claudia
authors.initials: C
authors.lastname: Steinem
mesh_terms: D000327:Adsorption; D017305:Annexin A1 / Q000737:chemistry*; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D003198:Computer Simulation; D008051:Lipid Bilayers / Q000737:chemistry*; D008567:Membranes, Artificial; D018625:Microscopy, Atomic Force; D008856:Microscopy, Fluorescence / Q000379:methods; D009010:Monte Carlo Method; D010316:Particle Size; D010713:Phosphatidylcholines / Q000737:chemistry*; D010718:Phosphatidylserines / Q000737:chemistry*; D013314:Stress, Mechanical; D013499:Surface Properties; D013997:Time Factors
chemical_list: D017305:Annexin A1; D008051:Lipid Bilayers; D008567:Membranes, Artificial; D010713:Phosphatidylcholines; D010718:Phosphatidylserines; C050294:1-palmitoyl-2-oleoylglycero-3-phosphoserine; C028694:1-palmitoyl-2-oleoylphosphatidylcholine