Gregory P. Holland
Assistant Professor, Analytical
office: GMCS 213C
- B.S., Chemistry, State University of New York at Buffalo, 1998
- Ph.D., Analytical and Physical Chemistry, University of Wyoming, 2003
- Postdoctoral Fellow, Sandia National Laboratories, 2003-2006
- Assistant Professor for Research, Arizona State University 2006-2015
- Assistant Professor at San Diego State University 2015-present
The Holland Lab explores the molecular structure and dynamics of complex biological and technologically relevant materials. We are interested in scientific problems that lie at the interface of chemistry, biology and materials science including biologically inspired materials and molecules and nanomaterials functionalized with biomolecules. Although we use a suite of characterization techniques to understand the systems of interest, the primary focus is on developing and applying nuclear magnetic resonance (NMR) methods. A continuing theme in our work is linking the role of molecular structure and dynamical features to material properties and biological function.
Spider silk: Spider silk is one of the toughest materials known. A spider produces this amazing material from an aqueous spinning dope at ambient temperature and pressure. Spiders produce a range of different silks with varying mechanical and physical properties. We have been utilizing a combination of magnetic resonance techniques to understand the molecular structure of the proteins that comprise the silks and further, to characterize the silk producing process as a whole. It is our belief that a better molecular-level understanding of the proteins' structure and biochemical processing conditions utilized to assemble the silk fiber will lead to a route for synthetic spider silk production.
Lipid Rafts: The viewpoint that cellular membranes are comprised of a continuous liquid crystalline phase of phospholipids is rapidly changing. In the past decade, strong evidence has been presented that supports the presence of heterogeneous domains that are rich in sphingomyelin and cholesterol within the plasma membrane. These domains have been coined "lipid rafts". It has been postulated that these rafts are functional platforms that perform a number of cellular processes. Lipid rafts have been implicated as potential sites for pathogen entry and toxin binding and have been linked to a number of diseases including Alzheimer's, Parkinson's, cardiovascular disease and HIV. We are studying model membrane mixtures that form lipid rafts to understand the molecular interactions involved in phase separation. Recently, we began investigating how protein neurotoxins bind and interact with these complex biological membrane mimics.
Spider Venom: Spiders are one of the most successful venomous animals on the planet. There have been over 40,000 species of spider described and each spider's venom contains hundreds to thousands of biologically active components. Our group has been focused on characterizing inhibitor cysteine knot (ICK) neurotoxins extracted from tarantula venom. These ICK peptides bind and modulate a diverse range of ion channels with high selectivity and affinity making them indispensible tools for elucidating the function of ion channels. We are studying the neurotoxin structures with conventional solution NMR and probing how they interact with model lipid membranes and channels with solid-state NMR approaches.
Nanomaterials: In the past decade, the synthesis, characterization and application of nanomaterials has become a major research area in the chemical and biological sciences with numerous research centers and institutions dedicated to this field. While many synthetic chemists and materials scientists have produced countless novel nanomaterials, the full characterization of the products is far less developed. We have been studying the fundamental chemistries both structural and dynamic at the interface of nanomaterials with NMR spectroscopy. A combination of solution- and solid-state NMR methods is implemented to elucidate the capping chemistry and organization of biomolecular ligands at the surface of nanomaterials. The primary goal of this work is to develop "easy to implement" NMR techniques to provide standard structural characterization for functionalized nanoparticles and nanomaterials.
- "Solid-state NMR Characterization of Mixed Phosphonic Acid Ligand Binding and Organization on Silica Nanoparticles," Langmuir 2016, (in press).
- "Cyclohexane Rings Reduce Membrane Permeability to Small Ions in Archaea-Inspired Tetraether Lipids," T. Koyanagi, G. Leriche, D. Onofrei, G.P. Holland, M.Mayer, J. Yang, Angew. Chem. Int. Ed. Engl. 2016, 55 1890-1893.
- "Alanine Adsorption and Thermal Condensation at the Interface of Fumed Silica Nanoparticles: A Solid-state NMR Investigation," C. Guo, G.P. Holland, J. Phys. Chem. C 2015, 119 25663-2567.
- "Extended Charge Carrier Lifetimes in Hierarchical Donor-Acceptor Supramolecular Polymer Films," C.X. Guzman, R.M.K. Calderon, Z. Li, S. Yamazaki, S.R. Peurifoy, C. Guo, S.K. Davidowski, M.M.A. Mazza, G.P. Holland, A.M. Scott, A.B. Braunschweig, J. Phys. Chem. C 2015, 119 19584-19589
- "Probing the Impact of Acidification on Spider Silk Assembly Kinetics," D. Xu; C. Guo; G.P. Holland, Biomacromolecules 2015, 16 2072-2079.
- "Molecular Dynamics of Spider Dragline Silk Fiber Investigated by 2H MAS NMR," X. Shi, G.P. Holland, J.L. Yarger, Biomacromolecules 2015, 16 852-859.
- "Investigating Lysine Adsorption on Fumed Silica Nanoparticles," C. Guo; G.P. Holland, J. Phys. Chem. C. 2014, 118 25792-25801.
- "Probing the Nature of Charge Transfer at Nano-Bio Interfaces: Peptides on Metal Oxide Nanoparticles," P. Tarakeshwar, J.L. Palma, G.P. Holland, P. Fromme, J.L. Yarger, V. Mujica, J. Phys. Chem. Lett. 2014, 5 3555-3559.
- "Reversible Assembly of β-sheet Nanocrystals within Caddisfly Silk," J.B. Addison, W.S. Weber, Q. Mou, N.N. Ashton, R.J. Stewart, G.P. Holland, J.L. Yarger, Biomacromolecules 2014, 15 1269-1275.
- "Structural Characterization of Nanofiber Silk Produced by Embiopterans (Webspinners)," J.B. Addison, T.M.O. Popp, W.S. Weber, J.S. Edgerly, G.P. Holland, J.L. Yarger, RSC Advances 2014, 4 41301-41313.
- "Elucidating Proline Dynamics in Spider Dragline Silk Fiber Using 2H-13C HETCOR MAS NMR," X. Shi; J.L. Yarger; G.P. Holland, Chem. Commun. 2014, 50 4856.
- "Exploring the Backbone Dynamics of Native Spider Silk Proteins in Black Widow Silk Glands with Solution-state NMR Spectroscopy," D. Xu; J.L. Yarger; G.P. Holland, Polymer, 2014, 55 3879.
- "Determining Hydrogen-bond Interactions in Spider Silk with 1H13C HETCOR fast MAS Solid-state NMR and DFT Proton Chemical Shift Calculations," G.P. Holland; Q. Mou; J.L. Yarger, Chem. Commun. 2013, 49 6680-6682.
- "Probing Lipid-cholesterol Interactions in DOPC/eSM/Chol and DOPC/DPPC/Chol Model Lipid Rafts with DSC and 13C Solid-state NMR," K.J. Fritzsching; J. Kim; G.P. Holland , Biochim. Biophys. Acta 2013, 1828 1889-1898.
- "Investigating Hydrogen-Bonded Phosphonic Acids with Proton Ultrafast MAS NMR and DFT Calculations," J.W. Blanchard; T.L. Groy; J.L. Yarger; G.P. Holland, J. Phys. Chem. C 2012, 116 18824-18830.