A5022656892- Mass Spectrometry Techniques and Applications
- Advanced Proteomics Techniques and Applications
- Analytical Chemistry and Chromatography
- Enzyme Structure and Function
- Supramolecular Chemistry and Complexes
- Metabolomics and Mass Spectrometry Studies
- Protein Structure and Dynamics
- Chemical Synthesis and Analysis
- Molecular Sensors and Ion Detection
- Advanced Chemical Physics Studies
- Redox biology and oxidative stress
- Connexins and lens biology
- Magnetism in coordination complexes
- Ion-surface interactions and analysis
- Alzheimer's disease research and treatments
- Molecular Junctions and Nanostructures
- Cellular transport and secretion
- Porphyrin and Phthalocyanine Chemistry
- Supramolecular Self-Assembly in Materials
- Amino Acid Enzymes and Metabolism
- Photochemistry and Electron Transfer Studies
- Protein purification and stability
- Reinforcement Learning in Robotics
- Crystallization and Solubility Studies
- Biochemical effects in animals
University of California, Riverside
2016-2025
Google (United States)
2023-2024
DeepMind (United Kingdom)
2024
University of California System
2010-2020
Riverside
2015-2020
College of Central Florida
2019
University of Central Florida
2019
University of California, Los Angeles
2010
Brigham Young University
2009
California Institute of Technology
2001-2008
Large language models can encode a wealth of semantic knowledge about the world. Such could be extremely useful to robots aiming act upon high-level, temporally extended instructions expressed in natural language. However, significant weakness is that they lack real-world experience, which makes it difficult leverage them for decision making within given embodiment. For example, asking model describe how clean spill might result reasonable narrative, but may not applicable particular agent,...
The rapid identification of proteins from biological samples is critical for extracting useful information in proteomics studies. Mass spectrometry one among the various methods choice achieving this task; however, current approaches are limited by a lack chemical control over gas phase. Herein, it shown that modification tyrosine to iodo-tyrosine followed UV photodissociation carbon−iodine bond can be used generate radial site specifically at modified residue. subsequent dissociation...
A self-assembled M2L4 palladium–pyridyl cluster with a "paddle-wheel" structure shows binding affinity in competitive organic solvents for neutral guests that possess both the correct size and electrostatic complementarity.
A crown ether based, photolabile radical precursor which forms noncovalent complexes with peptides has been prepared. The peptide/precursor can be electrosprayed, isolated in an ion trap, and then subjected to laser photolysis collision induced dissociation generate hydrogen deficient peptide radicals. It is demonstrated that these radicals behave very differently from the rich generated by electron capture methods. In fact, it shown side chain chemistry dictates both occurrence relative...
Self-assembly of a carboxylic acid-containing ligand into an Fe4L6 iminopyridine cage allows endohedral positioning the acid groups while maintaining robust structure. The is effective supramolecular catalyst, providing up to 1000-fold rate enhancement acetal solvolysis. This enhanced reactivity tandem deprotection/cage-to-cage interconversion that cannot be achieved with other catalysts. combination enhancements and sequestration reactive function confers both activity selectivity on...
Electrospray ionization sampling of 0.01 M solutions serine reveals an unusually abundant protonated octamer, which demonstrates a strong preference for homochirality. Ion mobility spectra yield experimental cross section that is consistent with single "cubic" structure. Density functional theory calculations support observations suggest the structure octamer closely related to and formed from small subsection crystal anhydrous serine. The formation, bonding, constraints placed on are...
A new method for identifying residue specific through space contacts as a function of protein secondary and tertiary structure in the gas phase is presented. Photodissociation non-native carbon−iodine bond incorporated into Tyr59 ubiquitin yields radical site specifically at that residue. The subsequent migration shown to be highly dependent on protein. Radical-directed dissociation (RDD) low charge states, which adopt compact structures, generates backbone fragmentation prominently...
Top-down ultraviolet photodissociation (UVPD) allows greater sequence coverage than any other currently available method, often fracturing the vast majority of peptide bonds in whole proteins. At same time, UVPD can be used to dissociate noncovalent complexes assembled from multiple proteins without breaking covalent bonds. Although utility these experiments is unquestioned, mechanism underlying seemingly contradictory results has been subject many discussions. Herein, some fundamental...
The presence of a single d-amino acid in peptide is very difficult to detect. Mass spectrometry-based approaches rely on differences fragmentation between all l-amino acid-containing peptides and (which are epimers) for identification. success this approach dependent the structural sensitivity method. Recently, experiments have demonstrated that initiated by radical chemistry, or radical-directed dissociation (RDD), particularly sensitive structure ion being fragmented. Herein, RDD used...
Abstract Highly selective, narcissistic self‐sorting can be achieved in the formation of self‐assembled cages rare earth metals with multianionic salicylhydrazone ligands. The assembly process is highly sensitive to length ligand and coordination geometry. Most surprisingly, high‐fidelity sorting possible between ligands identical angle geometry, differing only a single functional group on core, which not involved coordination. Supramolecular effects allow discrimination pendant functions as...
Proteinaceous aggregation is a well-known observable in Alzheimer's disease (AD), but failure and storage of lysosomal bodies within neurons equally ubiquitous actually precedes bulk accumulation extracellular amyloid plaque. In fact, AD shares many similarities with certain disorders though establishing biochemical connection has proven difficult. Herein, we demonstrate that isomerization epimerization, which are spontaneous chemical modifications occur long-lived proteins, prevent...
The discovery of several new unusually stable aggregates arginine that are intermolecularly bound by salt bridges is reported. Quadrupole ion-trap mass spectrometry provides evidence for the stability in zwitterionic state, where protonated guanidinium group one interacts strongly with carboxylate another to form noncovalent complexes, coordinated either a cation or anion. Clusters itself, sodium, potassium, lithium, magnesium, chloride, fluoride, bromide, iodide, and nitrate observed. DFT...
Site-specific fragmentation of peptides at phosphorylated serine or threonine residues is demonstrated. This radical directed cleavage accomplished by a two-step procedure. First the phosphate replaced with naphthalenethiol using well established Michael Addition chemistry. Second, modified peptide electrosprayed and subjected to irradiation 266 nm. Absorption naphthalene causes homolytic connecting carbon−sulfur bond yielding in β-position. Subsequent rearrangement cleaves backbone d-type...
Post-translational modifications that do not result in a change mass are particularly difficult to detect by spectrometry. For example, isomerization of aspartic acid or epimerization any chiral residue within peptide lead shifts but can be identified examination independently acquired tandem spectra combination with another technique. analysis biological sample, this means liquid chromatography some other type separation must used first separate the isomers from one another. Furthermore,...
Metal-selective self-assembly with rare-earth cations is possible suitable rigid, symmetrical bis-tridentate ligands. Kinetically controlled formation initially observed, smaller preferentially incorporated. Over time, the more thermodynamically favorable complexes larger metals are formed. This thermodynamic control a cooperative supramolecular phenomenon and only occurs upon multiple-metal-based self-assembly: single-metal ML3 analogues do not show reversible selectivity. The selectivity...
Top-down mass spectrometry (TD-MS) of intact proteins results in fragment ions that can be correlated to the protein primary sequence. Fragments generated either terminal fragments contain N- or C-terminus internal neither termini. Traditionally TD-MS experiments, generation has been avoided because ambiguity assigning these fragments. Here, we demonstrate experiments formed and assigned collision-based, electron-based, photon-based fragmentation methods are rich with sequence information,...
Abstract A self‐assembled Fe II 4 L 6 cage was synthesized with 12 internal amines in the cavity. The forms as dodeca‐ammonium salt, despite carrying an overall 8+ charge at metal centers, extracting protons from displaced water reaction. Despite this, basicity of is lower than their counterparts free solution. have a sliding scale basicity, ≈6 p K unit difference between first and last to be removed. This moderation side‐chain active site hallmark enzymatic catalysis.
Fucose is a signaling carbohydrate that attached at the end of glycan processing. It involved in range processes, such as selectin-dependent leukocyte adhesion or pathogen-receptor interactions. Mass-spectrometric techniques, which are commonly used to determine structure glycans, frequently show fucose-containing chimeric fragments obfuscate analysis. The rearrangement leading these fragments-often referred fucose migration-has been known for more than 25 years, but chemical identity...
Spontaneous chemical modifications in long-lived proteins can potentially change protein structure ways that impact proteostasis and cellular health. For example, isomerization of aspartic acid interferes with turnover is anticorrelated cognitive acuity Alzheimer's disease. However, few rates have been determined for Asp residues intact proteins. To remedy this deficiency, we used extracts from SH-SY5Y neuroblastoma cells as a source complex, brain-relevant proteome no baseline...
Recent advancements in large multimodal models have led to the emergence of remarkable generalist capabilities digital domains, yet their translation physical agents such as robots remains a significant challenge. This report introduces new family AI purposefully designed for robotics and built upon foundation Gemini 2.0. We present Robotics, an advanced Vision-Language-Action (VLA) model capable directly controlling robots. Robotics executes smooth reactive movements tackle wide range...
A new method for probing the equilibrium structures and folding states of proteins utilizing electrospray ionization mass spectrometry is described. Protein structure explored as a function side-chain availability determined by specific interaction between lysine 18-crown-6 ether (18C6). Various intramolecular interactions are competitive with lysine/18C6 can prevent noncovalent attachment 18C6. Changes to protein modify these inhibiting interactions, which leads change in number 18C6s that...