A5002731007- Ionosphere and magnetosphere dynamics
- Geophysics and Gravity Measurements
- Solar and Space Plasma Dynamics
- Photosynthetic Processes and Mechanisms
- Spectroscopy and Quantum Chemical Studies
- Photoreceptor and optogenetics research
- Photochemistry and Electron Transfer Studies
- Lipid Membrane Structure and Behavior
- Porphyrin Metabolism and Disorders
- Bacterial Genetics and Biotechnology
- Metal-Catalyzed Oxygenation Mechanisms
- Porphyrin and Phthalocyanine Chemistry
- Protein Structure and Dynamics
- Microbial Metabolic Engineering and Bioproduction
- Biofuel production and bioconversion
- Metalloenzymes and iron-sulfur proteins
- Supramolecular Self-Assembly in Materials
- Carbohydrate Chemistry and Synthesis
- Genomics and Phylogenetic Studies
- Electrochemical Analysis and Applications
- RNA and protein synthesis mechanisms
- Microbial Fuel Cells and Bioremediation
- Glycosylation and Glycoproteins Research
- Enzyme Catalysis and Immobilization
- Bacterial biofilms and quorum sensing
Argonne National Laboratory
2016-2025
Northwestern University
1997-2005
University of California, Riverside
2002
University of Rochester
1998
Cornell University
1994-1998
Indiana University – Purdue University Indianapolis
1997
Oak Ridge National Laboratory
1995
Walt Disney (United States)
1994
New forms of hydrophilic black silicon with superior bactericidal properties that can be tailored to selectively kill specific species.
Lignin is an abundant and recalcitrant component of plant cell walls. While lignin degradation in nature typically attributed to fungi, growing evidence suggests that bacteria also catabolize this complex biopolymer. However, the spatiotemporal mechanisms for catabolism remain unclear. Improved understanding biological process would aid our collective knowledge both carbon cycling microbial strategies valorize value-added compounds. Here, we examine modifications exoproteome three...
Bacterial gene expression is orchestrated by numerous transcription factors (TFs). Elucidating how regulated fundamental to understanding bacterial physiology and engineering it for practical use. In this study, a machine-learning approach was applied uncover the genome-scale transcriptional regulatory network (TRN) in Pseudomonas putida KT2440, an important organism bioproduction. We performed independent component analysis of compendium 321 high-quality profiles, which were previously...
Significance The remarkable near-unity quantum efficiency of photosynthetic charge separation has motivated decades research to uncover the underlying design principles. Much our current understanding is rooted in studies bacterial reaction center (BRC). We present two-dimensional electronic spectroscopy BRC as it undergoes separation, resolving energy-transfer and charge-separation processes with time excitation frequency resolution. These measurements reveal excitonic structure BRC,...
The engineering of biological pathways with man-made materials provides inspiring blueprints for sustainable fuel production. Here, we leverage a top-down cellular strategy to develop new semi-artificial photosynthetic paradigm carbon dioxide reduction via enveloping Halobacterium purple membrane-derived vesicles over Pd-deposited hollow porous TiO2 nanoparticles. In this biohybrid, the membrane protein, bacteriorhodopsin, not only retains its native function pumping protons but also acts as...
We report two-dimensional electronic spectroscopy (2DES) experiments on the bacterial reaction center (BRC) from purple bacteria, revealing hidden excitonic and vibronic structure. Through analysis of coherent dynamics BRC we resolve specific signatures that allow us to definitively assign upper exciton energy "special pair." This assignment is supported by simulations a reduced model BRC. The also identify nonsecular coherence transfer processes neglected in standard models photosynthetic...
Herein, we present a light-gated protocell model made of plasmonic colloidal capsules (CCs) assembled with bacteriorhodopsin for converting solar energy into electrochemical gradients to drive the synthesis energy-storage molecules. This synthetic incorporated an important intrinsic property noble metal particles, namely, resonance. In particular, near-field coupling between adjacent nanoparticles gave rise strongly localized electric fields and resulted in broad absorption whole visible...
We present computer simulations of excited state dynamics in models PS I and II which are based upon known structural spectral properties the antennae. In particular, these constrain pigment binding sites to three-dimensional volumes determined from molecular antenna complexes. The demonstrate that within a 10-30 ps after light absorption, rapid energy transfer among coupled chlorophylls leads quasiequilibrium fraction on any chlorophyll, normalized total remaining model, remains constant...
Symmetry-related branches of electron-transfer cofactorsinitiating with a primary electron donor (P) and terminating in quinone acceptors (Q)are common features photosynthetic reaction centers (RC). Experimental observations show activity only one themthe A branchin wild-type bacterial RCs. In mutant RC, we now demonstrate that transfer can occur along the entire, normally inactive B-branch pathway to reduce terminal acceptor QB on time scale nanoseconds. The transmembrane charge-separated...
Electron spin polarized electron paramagentic resonance (ESP EPR) spectra were obtained with deuterated iron-removed photosynthetic bacterial reaction centers (RCs) to specifically investigate the effect of rate primary charge separation, metal-site occupancy, and H-subunit content on observed P865+QA- charge-separated state. Fe-removed Zn-substituted RCs from Rb. sphaeroides R-26 prepared by refined procedures, specific transfer rates (kQ) intermediate acceptor H- QA (200 ps)-1 vs (3−6...
Intrinsic membrane proteins must usually be extracted from the native with aid of synthetic amphiphiles and then stabilized in a soluble form before detailed structural functional characterization is possible. We describe new unusual architectures that are useful for extraction stabilization photosynthetic protein superassemblies bacterial membranes. Our results suggest incorporating branch points both hydrophilic lipophilic portions can lead to favorable amphiphile behavior.
Integral membrane proteins (IMPs) are crucial biological components, mediating the transfer of material and information between cells their environment. Many IMPs have proven to be difficult isolate study. High-resolution structural on this class is limited, largely because difficulties in generating soluble forms such that retain native folding activity, high-quality crystals from preparations. Isolated typically do not dissolve aqueous solution, a property arises large patches hydrophobic...
Crystallization from lipidic mesophase matrices is a promising route to diffraction-quality crystals and structures of membrane proteins. The microfluidic approach reported here eliminates two bottlenecks the standard mesophase-based crystallization protocols: (i) manual preparation viscous mesophases (ii) harvesting often small fragile protein crystals. In here, protein-loaded are formulated in an X-ray transparent chip using only 60 nL solution per trial. transparency enables diffraction...
Bioinspired nanostructured materials that exhibit antimicrobial properties are being synthesized and tested at increasing rates for use in healthcare, manufacturing processes, diagnostics. Although progress has been made improving understanding their bactericidal activity, arguably, the biggest problem currently field is lack of a standard testing methodology allows optimal characterization better comparison emerging nanostructures. Here, we examine two forms silicon vary ability to kill...
Abstract Intraprotein electron transfer (ET) requires explicit local control of the environment cofactors to influence their intermolecular distances, relative orientations, and redox properties. Efficient, longer-range ET often utilizes molecular orbitals aromatic residues present in intervening space. Here, revitalization a vestigial pathway bacterial photosynthetic reaction center is achieved by scanning with tryptophans uncover markedly improved routes conduction key stabilizing step...
Photosynthetic reaction centers carry out a series of electron and proton transfer reactions that convert the energy light into high reduced products add to gradient. All photosynthetic (Photosystems I, II, Heliobacter, bacterial (bRCs)) have their charge separating cofactors arranged with two, c2-symmetric paths from primary donor terminal acceptor. In Type II (PSII bRCs), electrons utilize only one active branch. bRCs occurs in A branch excited state dimer P860 through BChlA, BPhA, QA,...
We report on the unexpected structural changes caused by substitution of acidic amino acids in Q(B) binding pocket bacterial photosynthetic reaction center alanines. The mutations targeted key residues L212Glu and L213Asp this transmembrane protein-cofactor complex. acid substitutions L212Ala-L213Ala mutant ("AA") were known to affect delivery protons after light-induced generation Q(B)(-), which renders AA strain incapable growth. structure not only revealed side chain rearrangements but...
Subpicosecond time-resolved absorption and steady-state resonance Raman studies are reported for Rhodobacter sphaeroides reaction centers (RCs) that incorporate the G(M203)D/L(M214)H double mutation (denoted DH). Upon excitation, P* decays with a time constant of 15 ps via combination electron transfer to L side (83%), decay ground state (10%), M form P+BPhM- (7%). On L-side, branching between charge recombination versus separation at transient intermediate reduces subsequent P+QA- yield...
The bacterial reaction center (BRC) serves as an important model system for understanding the charge separation processes in photosynthesis. Knowledge of electronic structure BRC is critical its mechanism. While it well-accepted that "special pair" pigments are strongly coupled, degree coupling among other has been thought to be relatively weak. Here we study W(M250)V mutant by two-color two-dimensional spectroscopy correlate changes Q x region with excitation y transitions. resulting y-Q...