School of Molecular Sciences

Seminars

Seminar schedules

All Seminars are at 3:40PM in PSH151, unless otherwise stated.

Previous Seminars

8/25/2017

Xu Wang
Arizona State University  School of Molecular Sciences
New Insights from Old GAGs: Studies in Glycosaminoglycans and Their Protein Partners

Abstract:
Glycosaminoglycans (GAG) are a unique class of linear, sulfated polysaccharides produced by many organisms. In humans, GAG act as receptors for numerous signaling proteins, allowing the glycan to control vital cellular processes such as migration, differentiation and regeneration. However, the structure-activity relationships of GAG-protein interactions are rarely clear, nor is there any way to determine the fine structures of intact GAG chains. These deficiencies have hampered our understanding of GAG’s biological role. Our group focuses on investigating biophysical factors governing GAG-protein interactions as well as on developing techniques to determine fine structures of intact GAG chains. So far, we have studied several important GAG-binding proteins, including the pro-inflammatory chemokine RANTES, the Lyme disease bacterium adhesin decorin-binding protein and the mitogenic cytokine pleiotrophin. Our results revealed mechanisms GAG use to regulate activities of these proteins and explained how structures of these proteins’ control their interactions with GAG. In addition, these studies shed light on the diverse nature of GAG-protein interactions and provide insights into the dynamic and adaptable qualities of these glycan-protein complexes.
Host: Neal Woodbury
9/1/2017

Xin-Yun Huang
Weill Cornell Medical College, Cornell University  
Fascin, Filopodia and Tumor Metastasis

Abstract:
Tumor metastasis is responsible for ~90% of all cancer deaths. One of the key steps during tumor metastasis is tumor cell migration and invasion. However, currently there is no anti-migration drug in clinical uses. Filopodia are finger-like cell surface extensions that are critical for cell migration. Fascin is the main actin-bundling protein in filopodia. Metastatic tumor cells are rich in filopodia, and the numbers of filopodia correlate with their invasiveness. From cancer genomics, fascin gene is amplified in patients with many types of cancers. Studies on samples from cancer patients demonstrate that elevated levels of fascin are correlated with clinically aggressive phenotypes, poor prognosis, and shorter survival. Mouse genetic studies showed that deletion of fascin gene delayed tumor development, slowed the tumor growth, reduced metastatic colonization, and increased overall survival. Transgenic expression of fascin in mice increased the tumor incidence, promoted tumor progression, and decreased the overall survival. We have developed small-molecule compounds that specifically inhibit the biochemical function of fascin. Fascin inhibitors block tumor cell migration, invasion and metastasis. These inhibitors alone, in combination with surgery, chemotherapy, or immunotherapy, all prolong the overall survival of tumor-bearing mice.
Host: Wei Liu
9/1/2017
11:00AM
PSH-132
Don Seo
Arizona State University  School of Molecular Sciences
Porous Sol-Gel Metal Oxides for Sustainability Applications – From Bio/Nano Hybrid-Based Solar Energy Conversion to Carbon Capture


Host: Neal Woodbury
9/8/2017

Carlos Castro
Ohio State Universty  
Design and Control of Dynamic DNA Nanomechanical Devices


Host: Nicholas Stephanopoulos
9/15/2017

Dennis Dougherty
California Institute of Technology  
Chemistry on the Brain: Understanding the Nicotine Receptor

Abstract:
The human brain is the most complex object known to man. It presents daunting challenges at all levels, from the anatomical, to the cellular, to the molecular. Our work seeks to provide a chemical-scale understanding of the molecules of memory, thought, and sensory perception; of Alzheimer’s, Parkinson’s, and schizophrenia. An area of particular interest has been the chemistry of nicotine addiction. The initial chemical event of nicotine addiction involves nicotine binding to and activating acetylcholine (ACh) receptors in the brain. Using the mindset and methodologies of physical organic chemistry, we have probed these complex membrane proteins with a precision and subtlety normally associated with small molecule studies. We have established that the cation-π interaction plays a pivotal role in promoting the high potency of nicotine in the brain, leading to its addictive properties. We have also discovered key hydrogen bonding interactions that uniquely contribute to the binding of nicotine to ACh receptors. These chemical studies provide a high-precision structural model for the interaction of potent drugs at brain receptors.
Host: Jeremy Mills
9/22/2017

Qinghai Zhang
Scripps Research Institute  
Chemical Tools Enabled ABC Transporter Structural Studies


Host: Wei Liu
9/29/2017

Thomas E. Mallouk
Penn State University  
Assembly and Disassembly of Layered Materials

Abstract:
Layered solids – which have strong bonds in two dimensions and weaker links in the third - are interesting building blocks for materials and devices because they potentially offer control over structure at the molecular level. Our research in this area began with the question of whether such compounds could be built up one layer at a time in controlled sequences on surfaces. This was possible by using either molecular precursors, in the case of metal phosphonates, or exfoliated sheets derived from lamellar microcrystals. Many layered oxides consist of negatively charged sheets interleaved by exchangeable cations. These oxides are particularly amenable to exfoliation (and to other topochemical reactions) by simple ion-exchange and acid-base reactions. Recently we have found that van der Waals solids such as graphite, hexagonal BN, and MoS2 can also be intercalated and exfoliated without incurring damage to the sheets by means of acid-base and redox reactions. An interesting consequence of the layer-by-layer assembly processes is the overcompensation of the surface charge of nanosheets. This effect can be exploited to invert the layer charge of nanosheets (which is typically negative for sheets derived from early transition metal oxides) and enable the intercalation of negatively charged molecules and nanoparticles. While studying these reactions, we observed surprisingly strong bonding between late transition metal oxide nanoparticles and early transition metal oxide nanosheets. Calorimetric measurements and electronic structure calculations suggest that d-acid/base interactions – originally proposed by Leo Brewer to explain the anomalous stability of early-late transition metal alloys – contribute to the strength of nanoparticle/nanosheet covalent bonding. This finding helps us understand the strong metal support interaction (SMSI) in catalysis and provides a prescription for stabilizing catalytically active late transition metal nanoparticles.
Host: Gary Moore
10/6/2017

Paul Cremer
Penn State University  
Metallomembranes: Exploring the Interactions of Metal Ions with Lipid Bilayers

Abstract:
Phosphatidylserine (PS) and phosphatidylethanolamine (PE) are major components of numerous cellular membranes. Both these lipids contain amine moieties in their head groups that can strongly interact with first row transition metal ions such as Cu2+. This is significant because copper is a redox active metal ion and causes lipid oxidation in the presence of oxidants such as hydrogen peroxide. To explore both the binding and oxidation chemistry of these systems, we have employed a combination of spectroscopic techniques (e.g. vibrational sum frequency and infrared spectroscopy), microfluidic platforms, fluorescence microscopy, as well as monolayer and planar supported bilayer architectures. This includes the development of a novel analytical tool that employs fluorescence quenching upon resonance energy transfer from a fluorophore to Cu2+ to quantitatively monitor metal ion binding at the bilayer surface. Both thermodynamic and molecular level details of these systems have been obtained. The results reveal that Cu2+ binding can be highly dependent on the concentration of PS within the membrane, the pH of the bulk solution, as well the ionic strength of the solution. Moreover, the presence or absence of various charged lipids can also greatly influence the binding properties. The interactions of transition metals with lipid membranes may play a role in neurodegenerative diseases such as Alzheimer’s as well as in Autism, where metal ion homeostasis is not maintained.
Host: Jia Guo
10/19/2017
Thursday
6:30PM
PSH-150
Richard Royce Schrock
MIT  
Eyring General Lecture: A Discovery and a Nobel Prize 30 years Later


Host: Neal Woodbury
10/20/2017

Richard Royce Schrock
MIT  
Eyring Technical Lecture: Recent Advances in Olefin Metathesis by Molybdenum and Tungsten Catalysts


Host: Neal Woodbury
10/27/2017

Ron Orlando
University of Georgia  
Challenges Associated with Glycoprotein Characterization: The More We Learn, the More We Realize How Much We Don’t Know

Abstract:
The ability to accurately quantitate the glycan chains attached to glycoproteins has wide-ranging implications. Numerous studies over the past 40 years have demonstrated that abnormal glycosylation occurs in virtually all types of human cancers, and show the potential of using glycan markers in either a diagnostic or a prognostic manner. The glycosylation on recombinant protein therapeutics is also known to have profound effects, with one of the better-known examples being the increased serum half-life of erythropoietin (EPO) resulting from glycoengineering. Hence, the quantification of glycoprotein glycans plays important roles from the discovery of new diagnostic/prognostic markers to the development of therapeutic agents. A particularly challenging aspect is the identification and accurate quantitation of low abundance glycans that are present as minor components in complex isomeric mixtures. We are developing analytical strategies to overcome the limitations encountered in traditional glycan profiling/glycomic analysis. The use of hydrophilic interaction liquid chromatography (HILIC) is a central component as this allows for the separation of isomeric glycan structures. To facilitate identification and discovery of low-level glycans, we have created a HILIC retention model for native glycans, peptides, and glycopeptides, which also facilitates the analysis of other hydrophilic post-translational modifications such as deamidation and isomerization. This presentation will highlight our approach and demonstrate its utility for the detection and quantitation of individual linkage isomers and other PTMs in complex mixtures such as human serum glycans and therapeutic IgGs.
Host: Chad Borges
11/3/2017

Thomas Meade
Northwestern University  
Seeing is Believing: Coordination Chemistry and Molecular Imaging: A Marriage made In Vivo


Host: Anne Jones
11/10/2017


 
Veterans Day-No seminar


Host:
11/17/2017

Adam Barb
Iowa State University  
Asparagine-linked Glycosylation of Immunoglobulin G and the Fc γ Receptors Impacts Immune System Activation


Host: Xu Wang
1/19/2018

William Shih
Harvard University  
TBA


Host: Nicholas Stephanopoulos
1/26/2018

Bill Graves
ASU  Physics
TBA


Host: Neal Woodbury
2/2/2018


 
TBA


Host:
2/9/2018


 
TBA


Host:
2/16/2018

Hannah Shafaat
Ohio State University  
TBA


Host: Anne Jones
2/23/2018


 
No seminar-visitation weekend


Host:
3/2/2018


 
TBA


Host:
3/9/2018


 
No seminar-spring break


Host:
3/16/2018

James C. Weisshaar
U. Wisconsin-Madison  
TBA


Host: Steve Pressé
3/23/2018


 
TBA


Host:
3/30/2018

David Baker
University of Washington  
Eyring Lecture


Host: Neal Woodbury and Jeremy Mills
4/6/2018

Jing Yang
UCSD  
TBA


Host: Jia Guo
4/13/2018

Juan Alfonzo
Ohio State University  
TBA


Host: Julian Chen
4/20/2018

Ayusman Sen
Penn State University  
TBA


Host: Steve Presse