A5003502962- Chemical Synthesis and Analysis
- RNA and protein synthesis mechanisms
- Advanced Polymer Synthesis and Characterization
- Click Chemistry and Applications
- Lipid Membrane Structure and Behavior
- Biotin and Related Studies
- Monoclonal and Polyclonal Antibodies Research
- Bacterial Genetics and Biotechnology
- biodegradable polymer synthesis and properties
- Polymer Surface Interaction Studies
- Cellular Mechanics and Interactions
- Synthesis and properties of polymers
- Supramolecular Self-Assembly in Materials
- Organometallic Complex Synthesis and Catalysis
- 3D Printing in Biomedical Research
- Hydrogels: synthesis, properties, applications
- Photopolymerization techniques and applications
- Bacteriophages and microbial interactions
- Synthetic Organic Chemistry Methods
- Protein Structure and Dynamics
- Pancreatic function and diabetes
- Biochemical and Structural Characterization
- Conducting polymers and applications
- RNA modifications and cancer
- Surfactants and Colloidal Systems
California Institute of Technology
2015-2024
Division of Chemistry
2008-2023
Pasadena City College
2015
Massachusetts Institute of Technology
2014
University of Massachusetts Amherst
1997-2013
Jacobs Institute
2007-2013
Rice University
2013
Royal Society of Chemistry
2012
Scripps Research Institute
2008-2010
Wesleyan University
2010
Recombinant DNA methods were used to create artificial proteins that undergo reversible gelation in response changes pH or temperature. The consist of terminal leucine zipper domains flanking a central, flexible, water-soluble polyelectrolyte segment. Formation coiled-coil aggregates the near-neutral aqueous solutions triggers formation three-dimensional polymer network, with segment retaining solvent and preventing precipitation chain. Dissociation through elevation temperature causes...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMicrocalorimetric detection of lower critical solution temperatures in aqueous polymer solutionsHoward G. Schild and David A. TirrellCite this: J. Phys. Chem. 1990, 94, 10, 4352–4356Publication Date (Print):May 1, 1990Publication History Published online1 May 2002Published inissue 1 1990https://pubs.acs.org/doi/10.1021/j100373a088https://doi.org/10.1021/j100373a088research-articleACS PublicationsRequest reuse permissionsArticle...
The introduction of chemically unique groups into proteins by means non-natural amino acids has numerous applications in protein engineering and functional studies. One method to achieve this involves the utilization a acid cell's native translational apparatus. Here we demonstrate that methionine surrogate, azidohomoalanine, is activated methionyl-tRNA synthetase Escherichia coli replaces expressed methionine-depleted bacterial cultures. We further show containing azidohomoalanine can be...
In both normal and pathological states, cells respond rapidly to environmental cues by synthesizing new proteins. The selective identification of a newly synthesized proteome has been hindered the basic fact that all proteins, old, share same pool amino acids thus are chemically indistinguishable. We describe here technology, based on cotranslational introduction azide groups into proteins chemoselective tagging azide-labeled with an alkyne affinity tag, separate identify, specifically, in...
Labeling of the cell surface Escherichia coli was accomplished by expression a recombinant outer membrane protein, OmpC, in presence unnatural amino acid azidohomoalanine, which acts as methionine surrogate. The surface-exposed azide moieties whole cells were biotinylated via Cu(1)-catalyzed [3+2] azide-alkyne cycloaddition. specificity labeling both wild-type OmpC and mutant containing additional sites for azidohomoalanine incorporation confirmed Western blotting. Flow cytometry performed...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCononsolvency in mixed aqueous solutions of poly(N-isopropylacrylamide)Howard G. Schild, M. Muthukumar, and David A. TirrellCite this: Macromolecules 1991, 24, 4, 948–952Publication Date (Print):February 1, 1991Publication History Published online1 May 2002Published inissue 1 February 1991https://pubs.acs.org/doi/10.1021/ma00004a022https://doi.org/10.1021/ma00004a022research-articleACS PublicationsRequest reuse permissionsArticle...
The combination of highly efficient polymerizations with modular "click" coupling reactions has enabled the synthesis a wide variety novel nanoscopic structures. Here we demonstrate facile new class clickable, branched nanostructures, polyethylene glycol (PEG)-branch-azide bivalent-brush polymers, facilitated by "graft-through" ring-opening metathesis polymerization norbornene-PEG-chloride macromonomer followed halide-azide exchange. resulting polymers possess azide groups at core near...
Graft-through ring-opening metathesis polymerization (ROMP) using ruthenium N-heterocyclic carbene catalysts has enabled the synthesis of bottle-brush polymers with unprecedented ease and control. Here we report first bivalent-brush polymers; these materials were prepared by graft-through ROMP drug-loaded polyethylene-glycol (PEG) based macromonomers (MMs). Anticancer drugs doxorubicin (DOX) camptothecin (CT) attached to a norbornene-alkyne-PEG MM via photocleavable linker. either or both...
Cells engage in mechanical force exchange with their extracellular environment through tension generated by the cytoskeleton. A method combining laser scanning confocal microscopy (LSCM) and digital volume correlation (DVC) enables tracking quantification of cell-mediated deformation matrix all three spatial dimensions. Time-lapse imaging migrating 3T3 fibroblasts on fibronectin (FN)-modified polyacrylamide gels varying thickness reveals significant in-plane (x, y) normal (z) displacements,...
The interactions between biochemical processes and mechanical signaling play important roles during various cellular such as wound healing, embryogenesis, metastasis, cell migration. While traditional traction force measurements have provided quantitative information about matrix in two dimensions, recent studies shown significant differences the behavior morphology of cells when placed three-dimensional environments. Hence new experimental techniques are needed to accurately determine...
Protein-based hydrogels have emerged as promising alternatives to synthetic for biomedical applications, owing the precise control of structure and function enabled by protein engineering. Nevertheless, strategies assembling 3D molecular networks that carry biological information encoded in full-length proteins remain underdeveloped. Here we present a robust gelation strategy based on pair genetically reactive partners, SpyTag SpyCatcher, spontaneously form covalent isopeptide linkages under...
Summary Here we describe the application of a new click chemistry method for fluorescent tracking protein synthesis in individual microorganisms within environmental samples. This technique, termed bioorthogonal non‐canonical amino acid tagging ( BONCAT ), is based on vivo incorporation L ‐azidohomoalanine AHA surrogate l ‐methionine, followed by labelling ‐containing cellular proteins azide‐alkyne chemistry. was evaluated with range phylogenetically and physiologically diverse archaeal...
Playing tag: Noncanonical amino acid tagging enables the selective fluorescent visualization of newly synthesized proteins in mammalian cells (see picture). Susceptibility to is determined by spatial and temporal character protein synthesis, thus providing a complement methods which identify relevant members proteome.
An improved protocol for copper-catalyzed triazole formation on the bacterial cell surface is described. Addition of highly pure CuBr to cells treated with azidohomoalanine (2) leads ca. 10-fold more extensive labeling than previously observed. This active catalyst allows detection methionine analogues azidoalanine (1), azidonorvaline (3), and azidonorleucine (4) in proteins. Azidoalanine was believed be silent regard cellular protein synthesis machinery.