A5086558273- Photosynthetic Processes and Mechanisms
- Spectroscopy and Quantum Chemical Studies
- Porphyrin and Phthalocyanine Chemistry
- Photoreceptor and optogenetics research
- Genetic diversity and population structure
- Photochemistry and Electron Transfer Studies
- Metal-Catalyzed Oxygenation Mechanisms
- Porphyrin Metabolism and Disorders
- CO2 Reduction Techniques and Catalysts
- Genetic and phenotypic traits in livestock
- Wildlife Ecology and Conservation
- Metalloenzymes and iron-sulfur proteins
- Amphibian and Reptile Biology
- ATP Synthase and ATPases Research
- Algal biology and biofuel production
- Light effects on plants
- Genetic Mapping and Diversity in Plants and Animals
- Molecular Biology Techniques and Applications
- Agricultural Systems and Practices
- Helminth infection and control
- Hemoglobin structure and function
- Coccidia and coccidiosis research
- Photodynamic Therapy Research Studies
- Genomics and Phylogenetic Studies
- Microbial Community Ecology and Physiology
Washington University in St. Louis
2015-2025
University of Missouri
2009-2015
High-resolution structures of reaction-center light-harvesting 1 complexes provide new insights into quinone dynamics.
Abstract Photosynthesis uses a limited range of the solar spectrum, so enhancing spectral coverage could improve efficiency light capture. Here, we show that hybrid reaction centre (RC)/yellow fluorescent protein (YFP) complex accelerates photosynthetic growth in bacterium Rhodobacter sphaeroides . The structure RC/YFP-light-harvesting 1 (LH1) shows position YFP attachment to RC-H subunit, on cytoplasmic side RC complex. Fluorescence lifetime microscopy whole cells and ultrafast transient...
The light-harvesting 2 complex (LH2) of the purple phototrophic bacterium Rhodobacter sphaeroides is a highly efficient, antenna that allows growth under wide-range light intensities. In order to expand spectral range this complex, we first used series competition assays measure capacity non-native pigments 3-acetyl chlorophyll (Chl) a, Chl d, f or bacteriochlorophyll (BChl) b replace native BChl in B800 binding site LH2. We then adjusted and systematically assessed pigments. find Arg−10 LH2...
The initial light-induced electron transfer (ET) steps in the bacterial photosynthetic reaction center (RC) have been extensively studied and provide a paradigm for connecting structure function. Although RCs local pseudo-C2 symmetry, ET only occurs along A branch of chromophores. Tyrosine M210 is key symmetry-breaking residue adjacent to bacteriochlorophyll BA that bridges primary donor P bacteriopheophytin acceptor HA. We used amber suppression incorporate phenylalanine variants with...
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...
Understanding the effects of substituents on natural photosynthetic pigments is essential for gaining a deep understanding why such were selected over course evolution use in systems. This knowledge should provide more thoughtful design artificial light-harvesting The hydrocarbon skeleton all chlorophylls phorbine, which contains an annulated five-membered (isocyclic) ring addition to reduced pyrrole characteristic chlorins. A phorbine and 131-oxophorbine (which bears oxo group isocyclic...
Assessing the effects of substituents on spectra chlorophylls is essential for gaining a deep understanding photosynthetic processes. Chlorophyll and b differ solely in nature 7-substituent (methyl versus formyl), whereas chlorophyll d 3-substituent (vinyl yet have distinct long-wavelength absorption maxima: 665 (a) 646 (b) 692 nm (d). Herein, spectra, singlet excited-state decay characteristics, results from DFT calculations are examined synthetic chlorins 13(1)-oxophorbines that contain...
Significance Photosynthetic organisms use pigment–protein complexes called reaction centers (RCs)—effectively nature’s solar cells—to convert the energy of sunlight into charge-separated species that power life processes. Whether from plants, algae, or photosynthetic bacteria, RCs feature 2 quasi-mirror-image arrangements protein and pigment cofactors. In purple photon-induced electron transfer (ET) reduces A-branch bacteriopheophytin (BPh) with near-unity quantum yield, while ET to...
Efficient light harvesting for molecular-based solar-conversion systems requires absorbers that span the photon-rich red and near-infrared (NIR) regions of solar spectrum. Reported herein are photophysical properties a set six chlorin-imides nine synthetic chlorin analogues extend absorption deeper (624–714 nm) into these key spectral regions. These help bridge gap between typical chlorins bacteriochlorins. The new compounds have high fluorescence quantum yields (0.15–0.34) long singlet...
Slow, ∼50 ps, P* → P+HA– electron transfer is observed in Rhodobacter capsulatus reaction centers (RCs) bearing the native Tyr residue at M208 and single amino acid change of isoleucine M204 to glutamic acid. The decay kinetics are unusually homogeneous (single exponential) room temperature. Comparative solid-state NMR [4′-13C]Tyr labeled wild-type M204E RCs show that chemical shift significantly altered mutant a manner consistent with formation hydrogen bond hydroxyl group. Models based on...
Significance Reaction centers (RCs) are critical to photosynthetic energy conversion. RCs in all characterized organisms contain two symmetrically arranged branches of chromophores and enable light-induced electron transfer with high yield. We fine-tune the properties a key bacterial RC symmetry-breaking tyrosine via its replacement noncanonical analogs determine kinetic outcomes. Results interpreted through energetic characterization made possible by resonance Stark spectroscopy. Analysis...
Seemingly redundant parallel pathways for electron transfer (ET), composed of identical sets cofactors, are a cornerstone feature photosynthetic reaction centers (RCs) involved in light-energy conversion. In native bacterial RCs, both A and B branches house one bacteriochlorophyll (BChl) bacteriopheophytin (BPh), but the branch is used exclusively. Described herein results obtained two Rhodobacter capsulatus RCs with an unnaturally high degree cofactor asymmetry, BPh on RC's side BChl side....
Abstract We report the isolation and characterization of 17 polymorphic microsatellite loci in North American raccoon ( Procyon lotor ). These exhibit high levels allelic diversity, with between four 13 alleles per locus, heterozygosity, observed values 0.500–1.000 a sample 20 individuals. All genotypes conformed to Hardy–Weinberg expectations there were no instances linkage disequilibrium detected.
Abstract The transfer of mitochondrial DNA (mtDNA) into nuclear genomes is a regularly occurring process that has been observed in many species. Few studies, however, have focused on the variation nuclear-mtDNA sequences (NUMTs) within This study examined mtDNA insertions chromosomes diverse set Zea mays ssp. (maize) inbred lines by use fluorescence situ hybridization. A relatively large NUMT long arm chromosome 9 (9L) was identified at approximately same position four (B73, M825, HP301, and...
Although black bears (Ursus americanus) were believed to be extirpated from the Interior Highlands of North America by early 1900s, populations have recently recovered, aided in part reintroductions Arkansas. Today can found Ozark and Ouachita National Forests northern western Arkansas, White River Wildlife Refuge eastern region southern Missouri. Previous genetic studies investigated effects translocating Minnesota Manitoba, Canada, into between 1958 1968, with differing results. We used...
Noninvasive sampling has revolutionized the study of species that are difficult or dangerous to using traditional methods. Early studies were often confined small populations as genotyping large numbers samples was prohibitively costly and labor intensive. Here we describe optimized protocols designed reduce costs effort required for microsatellite sex determination American black bears (Ursus americanus). We redesigned primers six loci, novel amelogenin gene genetic sex, conditions a...
The substantial electronic distinctions between bacteriochlorophyll (BChl) and its Mg-free analogue bacteriopheophytin (BPh) are exploited in two sets of Rhodobacter capsulatus reaction center (RC) mutants that contain a heterodimeric BChl–BPh primary electron donor (D). BPh component the M-heterodimer (Mhd) or L-heterodimer (Lhd) obtains from substituting Leu for His M200 L173, respectively. Lhd-β Mhd-β RCs serve as initial templates mutant sets, where β denotes L-side acceptor (HL) has...
The primary electron transfer (ET) processes at 295 and 77 K are compared for the Rhodobacter sphaeroides reaction center (RC) pigment–protein complex from 13 mutants including a wild-type control. engineered RCs bear mutations in L M polypeptides that largely inhibit ET excited state P* of donor (P, bacteriochlorophyll dimer) to normally photoactive A-side cofactors enhance C2-symmetry related, photoinactive, B-side cofactors. decay is multiexponential both temperatures modeled as arising...