title: Structure and Dynamics of Antifreeze Protein--Model Membrane Interactions: A Combined Spectroscopic and Molecular Dynamics Study.
abstract: Antifreeze proteins (AFPs) are the key biomolecules that enable species to survive under subzero temperature conditions. The physiologically relevant activities of AFPs are based on the adsorption to ice crystals, followed by the inhibition of subsequent crystal layer growth of ice, routed with depression in freezing point in a noncolligative manner. The functional attributes governing the mechanism by which AFPs inhibit freezing of body fluids in bacteria, fungi, plants, and fishes are mainly attributed to their adsorption onto the surface of ice within the physiological system. Importantly, AFPs are also known for their application in cryopreservation of biological samples that might be related to membrane interaction. To date, there is a paucity of information detailing the interaction of AFPs with membrane structures. Here, we focus on elucidating the biophysical properties of the interactions between AFPs and micelle models that mimic the membrane system. Micelle model systems of zwitterionic DPC and negatively charged SDS were utilized in this study, against which a significant interaction is experienced by two AFP molecules, namely, Peptide 1m and wfAFP (the popular AFP sourced from winter flounder). Using low- and high-resolution biophysical characterization techniques, such as circular dichroism (CD) and NMR spectroscopy, a strong evidence for the interactions of these AFPs with the membrane models is revealed in detail and is corroborated by in-depth residue-specific information derived from molecular dynamics simulation. Altogether, these results not only strengthen the fact that AFPs interact actively with membrane systems, but also demonstrate that membrane-associated AFPs are dynamic and capable of adopting a number of conformations rendering fluidity to the system.
authors.affiliation: Department of Biophysics, Bose Institute , P-1/12 CIT Scheme VII (M), Kolkata 700 054, India.
authors.forename: Rajiv K
authors.initials: RK
authors.lastname: Kar
authors.affiliation: Biophysics and Department of Chemistry, University of Michigan , Ann Arbor, Michigan 48109, United States.
authors.forename: Kamal H
authors.initials: KH
authors.lastname: Mroue
authors.affiliation: Center of Biomedical Magnetic Resonance, Sanjay Gandhi Post-Graduate Institute of Medical Sciences Campus , Lucknow 226014, India.
authors.forename: Dinesh
authors.initials: D
authors.lastname: Kumar
authors.affiliation: Department of Biotechnology, Surya University , Tangerang 15810, Indonesia.
authors.forename: Bimo A
authors.initials: BA
authors.lastname: Tejo
authors.affiliation: Department of Biophysics, Bose Institute , P-1/12 CIT Scheme VII (M), Kolkata 700 054, India.
authors.forename: Anirban
authors.initials: A
authors.lastname: Bhunia
mesh_terms: D021301:Antifreeze Proteins / Q000737:chemistry*; D002942:Circular Dichroism; D009682:Magnetic Resonance Spectroscopy; D056004:Molecular Dynamics Simulation; D011487:Protein Conformation; D013113:Spin Labels
chemical_list: D021301:Antifreeze Proteins; D013113:Spin Labels