Julian W. Snow, PhD
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Julian W. Snow
Professor
Ph.D., Physical Chemistry
University of California at Santa Barbara, 1975
Physical Biochemistry
Biochemistry
Physical Chemistry
Griffith 160
215.596.8837
j.snow@usp.edu
Snow Website
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Research Interests
- Structure of serum apolipoproteins
- Serum apolipoprotein-lipid interactions
- Thermodynamics of amphiphile-membrane interactions
Research Summary
Relationships between protein structure and function have long been studied with a variety of techniques. Scanning calorimetry (DSC) and its newer cousin, isothermal titration calorimetry (ITC), are capable of yielding a wealth of thermodynamic information about the structures of these macromolecules. These techniques, along with fluorescence and UV-VIS spectroscopy, are used in this lab to study structural properties of exchangeable serum apolipoproteins (apo-A, apo-E) associated with high-density lipoprotein (HDL). Since HDL is known to be involved in reverse cholesterol transport, i.e., transport of cholesterol from peripheral tissue to liver, such studies are of interest in the elucidation of molecular events associated with heart disease. DSC, for example, is being used to study the thermal unfolding of various isoforms of apo-E in order to learn about the structures and stabilities of secondary structural motifs that occur in the tertiary structures of the proteins, and also to study the structural changes that are brought about by the few amino acid substitutions that constitute the differences in sequence between these isoforms. ITC and fluorescence whenever possible, are used to learn about the interactions between exchangeable apolipoproteins with phospholipid. Smaller model compounds, such as amphipathic helical peptides, are also used in such studies in an attempt to learn about such important thermodynamic properties as binding constants, or partition coefficients, free energies, enthalpies and entropies, and also heat capacities of interaction.
Recent or Representative Publications
‡ Undergraduate Student
* Graduate Student
J.A. Gazzara*, M.C. Phillips, S. Lund-Katz, M.N. Palgunachari, J.P. Segrest, G.M. Anantharamaiah, and J. Snow, 1997, "Interaction of Class A Amphipathic Helical Peptides with Phospholipid Unilamellar Vesicles," J. Lipid Res., 38, 2134 - 2146.
J.A. Gazzara*, M.C. Phillips, S. Lund-Katz, M.N. Palgunachari, J.P. Segrest, G.M. Anantharamaiah, W.V. Rodrigueza, and J. Snow, 1997, "Effect of Vesicle Size on their Interaction with Class A Amphipathic Helical Peptides," J. Lipid. Res., 38, 2147 - 2154.
C.A. Veloski, R.A. McCann,. and J.W. Snow, 1994, "An Analytical Model forthe Phase Behavior of Cholesteryl Esters in Intracellular Inclusions," Biochim. Biophys. Acta, 1213, 183 - 192.
J.W. Snow, J.M. Glick, and M.C. Phillips, 1992, "The Phase Behavior of Cholesteryl Esters in Intracellular Inclusions," J. Biol. Chem., 267, 18564 - 18572.