研究领域
Bioanalytical/Biophysical Chemistry
Research in my group arises from my interest in polyelectrolytes, long-chain molecules in which every repeat unit carries a charge. Their unique properties reflect a combination of those of polymer solutions and salts. We focus on their interaction with oppositely charged nanoparticles such as dendrimers, surfactant micelles and proteins, with the objective of fundamental understanding of solution behavior. To do this we measure properties that can be quantitatively understood through basic physical relationships. Our work combines the disciplines of analytical, biological and physical chemistry.
Our experimental tools vary from very simple ones (turbidimetry), to more complex methods (light scattering, capillary electrophoresis, rheology, and various microscopies). To ensure reproducible results, we focus on equilibrium systems. One of our interests is the unique dense, viscous liquid phase “coacervates” that form spontaneously from polyelectrolytes with oppositely charged micelles or proteins. Polyelectrolyte-enzyme coacervates function as microreactors because the protein retains its native state and diffuses freely in the dense fluid coacervatge droplets. The surprising combination of high viscosity and fast diffusion arises from mesophase separation at the 300 nm length scale in these fluids. Polyelectrolyte-micelle coacervates also display unusual properties, phase separating by either heating or stress, a phenomenon known as “shear-banding.”
Biologically significant protein binding occurs with a group of polyelectrolytes known as glycosaminoglycans (GAGs). These mammalian polysaccharides are the most highly charged macromolecules in animals. Although they play a role in the action of many signaling proteins responsible for tissue regeneration, angiogenesis and cell differentiation, structure-property relations for GAGs are unknown. Unlike proteins and nucleic acids, they are never homogeneous and therefore never “pure,” so their characterization presents a huge challenge to classical biochemistry. We approach this problem with the model GAG-protein system of heparin-antithrombin, applying electrophoretic methods coupled with mass spectrometry and protein modeling.
近期论文
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S. Flanagan, A. Malanowski, E. Kizilay, D. Seeman, P.L. Dubin, L. Donato-Capel, L. Bovetto, C. Schmitt. "Complex Equilibria, Speciation, and Heteroprotein Coacervation of Lactoferrin and β-lactoglobulin." Langmuir, (2015) (epub ahead of print)
E. Kizilay, D. Seeman, Y. Yan, X. Du, P.L. Dubin, and C. Schmitt. "Structure of Bovine β-Lactoglobulin/Lactoferrin Coacervates" Soft Matter, (2014) 10, 7262-7268
X. Du, P.L. Dubin, D.A. Hoagland, and L. Sun. "Protein-Selective Coacervation with Hyaluronic Acid". Biomacromolecules, (2014) 15(3):726-34.
B.B. Minsky , B. Zheng , and P.L. Dubin. "Inhibition of Antithrombin and Bovine Serum Albumin Native State Aggregation by Heparin". Langmuir, 30 (1), pp 278–287 (2014)
Y. Yan, E. Kizilay, D. Seeman, S. Flanagan, P.L. Dubin, L. Bovetto, L. Donato, and C. Schmitt. "Heteroprotein Complex Coacervation: Bovine β-Lactoglobulin and Lactoferrin". Langmuir, 29 (50), pp 15614–15623 (2013)
E. Kizilay, A.D. Dinsmore, D.A. Hoagland, L. Sun, P.L. Dubin. "Evolution of hierarchical structures in polyelectrolyte–micelle coacervates". Soft Matter,9, 7320-7332 (2013)
B.B. Minsky, T.V. Nguyen, S.R. Peyton, I.A. Kaltashov, and P.L. Dubin. "Heparin Decamer Bridges a Growth Factor and an Oligolysine by Different Charge-Driven Interactions". Biomacromolecules, 14 (11), pp 4091–4098 (2013)
Y. Xu, Y. Engel, Y. Yan, K. Chen, D.F. Moyano, P.L. Dubin, V. M. Rotello. "Enhanced electrostatic discrimination of proteins on nanoparticle-coated surfaces". J. Mater. Chem. B, 2013, 1, 5230-5234 (2013)
Y. Yan, D. Seeman, B. Zheng, E. Kizilay, Y. Xu, P.L. Dubin. "pH-Dependent Aggregation and Disaggregation of Native β-Lactoglobulin in Low Salt". Langmuir, 29 (14), pp 4584–4593 (2013)
B.B. Minsky, A. Atmuri, I.A. Kaltashov, P.L. Dubin. "Counterion condensation on heparin oligomers". Biomacromolecules, 14 (4), pp 1113–1121 (2013)
A.B. Kayitmazer, D. Seeman, B.B. Minsky, P.L. Dubin, Y. Xu. "Protein–polyelectrolyte interactions". Soft Matter, 9 (2013), 2553-2583
Y. Xu, D. Seeman, Y. Yan, L. Sun, J. Post, P.L. Dubin. "Effect of Heparin on Protein Aggregation: Inhibition versus Promotion". Biomacromolecules, 13 (2012), 1642-1651
Y. Xu, Y. Yan, D. Seeman, L. Sun, P.L. Dubin. "Multimerization and Aggregation of Native Insulin: Effect of Zinc". Langmuir, (2012) 28(1):579-86
E. Kizilay, A.B. Kayitmazer, P.L. Dubin. "Complexation and coacervation of polyelectrolytes with oppositely charged colloids". ACIS, 167 (2011) 24-37
K. Chen, Y.Xu, S. Rana, O. R. Miranda, P. L. Dubin, V. M. Rotello, L. Sun, and X. Guo. "Electrostatic Selectivity in Protein−nanoparticle Interactions". Biomacromolecules, 12 (2011) 2552-2561
Y.Xu, M. Mazzawi, K. Chen, L. Sun, and P.L. Dubin. "Protein Purification by Polyelectrolyte Coacervation: Influence of Protein Charge Anisotropy on Selectivity". Biomacromolecules, 12 (2011) 1512-1522.
E. Kizilay, S. Maccarrone, E. Foun, A. D. Dinsmore, and P. L. Dubin, "Cluster Formation in Polyelectrolyte-Micelle Complex Coacervation". J.Phys. Chem. 115 (2011) 7256-7263
A.B. Kayitmazer, B. Quinn, K. Kimura R.Tate, D. Pink, and P.L. Dubin, "Charge Sequence Specificity for Protein Binding by Polyanions vs. Heparin", Biomacromolecules, 11, (2010) 3325-3331
R. Silva, M. Urzúla, D.F.S. Petri, and P.L. Dubin, Langmuir, "Protein adsorption onto polyelectrolyte layers: effects of protein hydrophobicity and charge anisotropy", 26 (2010) 14032-8.
E. Seyrek, P.L. Dubin, E. Seyrek, "Glycosaminoglycans as Polyelectrolytes", Advances in Colloid and Interface Science,.158 (2010) 119-129
M. Antonov, M. Mazzawi, and P.L. Dubin, "Entering and exiting the coacervate phase: Non-monotonic salt dependence of critical conditions for coacervation in a protein-polyelectrolyte system", Biomacromolecules, 11, 51-9 (2010).
O. G. Jones, U.Lesmes, P. Dubin, D. J. McClements, "Effect of polysaccharide charge on formation and properties of biopolymer nanoparticles created by heat treatment of b-lactoglobulin pectin complexes," Food Hydrocolloids, 24, 374-383 (2010).
M. W. Liberatore, N. B. Wyatt, M.Henry and E. Foun, "Shear-induced Phase Separation in Polyelectrolyte-Mixed Micelle Coacervates", Langmuir 25, 76-83 (2009).
P.L. Dubin, Y. Li and W. Jaeger, "Mesophase separation in polyelectrolyte-mixed micelles coacervates", Langmuir 24, 4544-4549(2008).
Menjoge, A. R.; Kayitmazer, A.B.; Dubin, P.L.; Jaeger, W.; Vansenkov, S. "Heterogeneity of Polyelectrolyte Diffusion in Polyelectrolyte-Protein Coacervates: A 1H Pulsed Field Gradient NMR Study", J. Phys. Chem. B 112, 4961-4966 (2008).
Giger, K.; Vanam, R.; Seyrek, E.; Dubin, P.L., "Suppression of Insulin Aggregation by Heparin", Biomacromolecules. 9, 2338-2344 (2008).
Y.G. Mishael, P.D. Dubin, R. deVries and A.B. Kayitmazer, "Effect of Pore Size on Polyelectrolyte Adsorption on/in Controlled Pore Glass", Langmuir 23, 2510-2516 (2007).
E. Seyrek, J. Henriksen and P.L Dubin, "Nonspecific Electrostatic Binding Characteristics of the Heparin-Antihrombin Interaction", Biopolymers 86, 249-259 (2007).
A. Kumar, M. Hernon, W. Jaeger and P.L. Dubin, "Temperature-dependent Phase Behavior of Polyelectrolyte-mixed Micelle Systems", J. Phys. Chem. B., 111, 8648-8676 (2007).
A.B. Kayitmazer, H. Bohidar, A. Bose, A. Hashidzume, P.Russo, W. Jaeger and P.L. Dubin, "Mesophase Separation and Probe Dynamics in Protein-polyelectrolyte Coacervates", Soft Matter 3, 1064-1076 (2007).
R. Abzalimov, P.L. Dubin and I. Kaltashov, "Glycosaminoglycans as naturally occurring combinatorial libraries: developing a mass spectrometry-based strategy for characterization of anti-thrombin interaction with low molecular weight heparin and heparin oligomers", Anal. Chem. 79, 6055-6063 (2007).
A.B. Kayitmazer, S.Strand, C. Tribet, W. Jaeger, P.L. Dubin, "Effect of Polyelectrolyte Structure on Protein-Polyelectrolyte Coacervates: Coacervates of Bovine Serum Albumin with Poly(dimethyldiallylammonium chloride) vs. Chitosan", Biomacromolecules, 8, 3568-3577(2007).
P. Mahji, R. R. Ganta, R. P. Vanam, E. Seyrek, K. Giger and P.L. Dubin , "Electrostatically Driven Protein Aggregation: b-Lactoglobulin at Low Ionic Strength", Langmuir 22, 9150-9159 (2006).
X. Guo, G.F. Kirton and P.L. Dubin, "Carboxylated ficolls: Synthesis, characterization, and electrophoretic behavior of model charged nanospheres", J. Phys. Chem. B, 110, 20815-20822 (2006).
C.L. Cooper, A. Goulding, A.B. Kayitmazer, S. Stoll, S. Turksen, S. Ulrich, S.-I. Yusa, A. Kumar and P.L. Dubin, "Effects of Polyelectrolyte Chain Stiffness, Charge Mobility and Charge Sequences on Binding to Proteins and Micelles", Biomacromolecules 7(4), 1025-1035 (2006).
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