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- G-quadruplex (3)
- Fluorescence (2)
- G-quadruplex DNA (2)
- Aggregation (1)
- Anti-cancer therapy (1)
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- DNA structure (1)
- End-stacking (1)
- Enthalpy (1)
- Entropy (1)
- Gallium (1)
- Group 13 metals (1)
- Human telomeric DNA (1)
- Lewis acid (1)
- Light switch (1)
- Light switch effect (1)
- Macrocyclic compounds (1)
- Metalloporphyrin (1)
- Mitochondrial disease (1)
- Mitochondrial genome instability (1)
- MtDNA deletions (1)
- N-methyl mesoporphyrin IX (1)
- Non-B DNA (1)
- Non-innocent ligand (1)
- Nuclear magnetic resonance (NMR) (1)
- Nucleic acid structures (1)
- Oncogene (1)
- Parallel G-quadruplex (1)
- Physical and chemical processes (1)
- Reaction mechanism (1)
- Redox-active ligand (1)
Articles 1 - 23 of 23
Full-Text Articles in Inorganic Chemistry
Water Spines And Networks In G-Quadruplex Structures, Kevin Li , '22, Liliya A. Yatsunyk, S. Neidle
Water Spines And Networks In G-Quadruplex Structures, Kevin Li , '22, Liliya A. Yatsunyk, S. Neidle
Chemistry & Biochemistry Faculty Works
Quadruplex DNAs can fold into a variety of distinct topologies, depending in part on loop types and orientations of individual strands, as shown by high-resolution crystal and NMR structures. Crystal structures also show associated water molecules. We report here on an analysis of the hydration arrangements around selected folded quadruplex DNAs, which has revealed several prominent features that re-occur in related structures. Many of the primary-sphere water molecules are found in the grooves and loop regions of these structures. At least one groove in anti-parallel and hybrid quadruplex structures is long and narrow and contains an extensive spine of linked …
Biophysical And X-Ray Structural Studies Of The (Gggtt)3ggg G-Quadruplex In Complex With N-Methyl Mesoporphyrin Ix, Linda Yingqi Lin , '20, S. Mccarthy, Barrett M. Powell , '18, Yanti Manurung , '20, Irene M. Xiang , '18, W. L. Dean, B. Chaires, Liliya A. Yatsunyk
Biophysical And X-Ray Structural Studies Of The (Gggtt)3ggg G-Quadruplex In Complex With N-Methyl Mesoporphyrin Ix, Linda Yingqi Lin , '20, S. Mccarthy, Barrett M. Powell , '18, Yanti Manurung , '20, Irene M. Xiang , '18, W. L. Dean, B. Chaires, Liliya A. Yatsunyk
Chemistry & Biochemistry Faculty Works
The G-quadruplex (GQ) is a well-studied non-canonical DNA structure formed by G-rich sequences found at telomeres and gene promoters. Biological studies suggest that GQs may play roles in regulating gene expression, DNA replication, and DNA repair. Small molecule ligands were shown to alter GQ structure and stability and thereby serve as novel therapies, particularly against cancer. In this work, we investigate the interaction of a G-rich sequence, 5’-GGGTTGGGTTGGGTTGGG-3’ (T1), with a water-soluble porphyrin, N-methyl mesoporphyrin IX (NMM) via biophysical and X-ray crystallographic studies. UV-vis and fluorescence titrations, as well as a Job plot, revealed a 1:1 binding stoichiometry with an …
G-Quadruplex Dynamics Contribute To Regulation Of Mitochondrial Gene Expression, M. Falabella, J. E. Kolesar, C. Wallace, D. De Jesus, L. Sun, Y. V. Taguichi, C. Wang, T. Wang, Irene M. Xiang , '18, J. K. Alder, R. Maheshan, W. Horne, Joshua R. Turek-Herman , '16, P. J. Pagano, C. M. St. Croix, N. Sondheimer, Liliya A. Yatsunyk, F. B. Johnson, B. A. Kaufman
G-Quadruplex Dynamics Contribute To Regulation Of Mitochondrial Gene Expression, M. Falabella, J. E. Kolesar, C. Wallace, D. De Jesus, L. Sun, Y. V. Taguichi, C. Wang, T. Wang, Irene M. Xiang , '18, J. K. Alder, R. Maheshan, W. Horne, Joshua R. Turek-Herman , '16, P. J. Pagano, C. M. St. Croix, N. Sondheimer, Liliya A. Yatsunyk, F. B. Johnson, B. A. Kaufman
Chemistry & Biochemistry Faculty Works
Single-stranded DNA or RNA sequences rich in guanine (G) can adopt non-canonical structures known as G-quadruplexes (G4). Mitochondrial DNA (mtDNA) sequences that are predicted to form G4 are enriched on the heavy-strand and have been associated with formation of deletion breakpoints. Increasing evidence supports the ability of mtDNA to form G4 in cancer cells; however, the functional roles of G4 structures in regulating mitochondrial nucleic acid homeostasis in non-cancerous cells remain unclear. Here, we demonstrate by live cell imaging that the G4-ligand RHPS4 localizes primarily to mitochondria at low doses. We find that low doses of RHPS4 do not induce …
N-Methyl Mesoporphyrin Ix As A Highly Selective Light-Up Probe For G-Quadruplex Dna, Ariana Yett , '21, Linda Yingqi Lin , '20, Dana Beseiso , '21, Joanne Miao , '22, Liliya A. Yatsunyk
N-Methyl Mesoporphyrin Ix As A Highly Selective Light-Up Probe For G-Quadruplex Dna, Ariana Yett , '21, Linda Yingqi Lin , '20, Dana Beseiso , '21, Joanne Miao , '22, Liliya A. Yatsunyk
Chemistry & Biochemistry Faculty Works
N-methyl mesoporphyrin IX (NMM) is a water-soluble, non-symmetric porphyrin with excellent optical properties and unparalleled selectivity for G-quadruplex (GQ) DNA. G-quadruplexes are non-canonical DNA structures formed by guanine-rich sequences. They are implicated in genomic stability, longevity, and cancer. The ability of NMM to selectively recognize GQ structures makes it a valuable scaffold for designing novel GQ binders. In this review, we survey the literature describing the GQ-binding properties of NMM as well as its wide utility in chemistry and biology. We start with the discovery of the GQ-binding properties of NMM and the development of NMM-binding aptamers. We then discuss …
Mechanism For Copper(Ii)-Mediated Disaggregation Of A Porphyrin J-Aggregate, M. Trapani, I. G. Occhiuto, R. Zagami, G. De Luca, M. A. Castriciano, A. Romeo, L. M. Scolaro, Robert F. Pasternack
Mechanism For Copper(Ii)-Mediated Disaggregation Of A Porphyrin J-Aggregate, M. Trapani, I. G. Occhiuto, R. Zagami, G. De Luca, M. A. Castriciano, A. Romeo, L. M. Scolaro, Robert F. Pasternack
Chemistry & Biochemistry Faculty Works
J-aggregates of anionic meso-tetrakis(4-sulfonatophenyl)porphyrin form at intermediate pH (2.3–3.1) in the presence of NiSO₄ or ZnSO₄ (ionic strength, I.S. = 3.2 M). These aggregates convert to monomeric porphyrin units via metallation with copper(II) ions. The kinetics for the disassembly process, as monitored by UV/vis spectroscopy, exhibits zeroth-order behavior. The observed zeroth-order rate constants show a two-term dependence on copper(II) ion concentrations: linear and second order. Also observed is an inverse dependence on hydrogen ion concentration. Activation parameters have been determined for the disassembly process leading to ΔH^≠ = (+163 ± 15) kJ·mol⁻¹ and ΔS^≠ = (+136 ± 11) J·K⁻¹. A …
Interactions Between Spermine-Derivatized Tentacle Porphyrins And The Human Telomeric Dna G-Quadruplex, Navin C. Sabharwal , '14, Jessica Chen , '17, Joo Hyun Lee , '17, C. M. A. Gangemi, A. D'Urso, Liliya A. Yatsunyk
Interactions Between Spermine-Derivatized Tentacle Porphyrins And The Human Telomeric Dna G-Quadruplex, Navin C. Sabharwal , '14, Jessica Chen , '17, Joo Hyun Lee , '17, C. M. A. Gangemi, A. D'Urso, Liliya A. Yatsunyk
Chemistry & Biochemistry Faculty Works
G-rich DNA sequences have the potential to fold into non-canonical G-Quadruplex (GQ) structures implicated in aging and human diseases, notably cancers. Because stabilization of GQs at telomeres and oncogene promoters may prevent cancer, there is an interest in developing small molecules that selectively target GQs. Herein, we investigate the interactions of meso-tetrakis-(4-carboxysperminephenyl)porphyrin (TCPPSpm4) and its Zn(II) derivative (ZnTCPPSpm4) with human telomeric DNA (Tel22) via UV-Vis, circular dichroism (CD), and fluorescence spectroscopies, resonance light scattering (RLS), and fluorescence resonance energy transfer (FRET) assays. UV-Vis titrations reveal binding constants of 4.7 × 10⁶ and 1.4 × 10⁷ M⁻¹ and binding stoichiometry of …
Quadruplexes In ‘Dicty’: Crystal Structure Of A Four-Quartet G-Quadruplex Formed By G-Rich Motif Found In The Dictyostelium Discoideum Genome, A. Guédin, Linda Yingqi Lin , '20, S. Armane, L. Lacroix, J.-L. Mergny, S. Thore, Liliya A. Yatsunyk
Quadruplexes In ‘Dicty’: Crystal Structure Of A Four-Quartet G-Quadruplex Formed By G-Rich Motif Found In The Dictyostelium Discoideum Genome, A. Guédin, Linda Yingqi Lin , '20, S. Armane, L. Lacroix, J.-L. Mergny, S. Thore, Liliya A. Yatsunyk
Chemistry & Biochemistry Faculty Works
Guanine-rich DNA has the potential to fold into non-canonical G-quadruplex (G4) structures. Analysis of the genome of the social amoeba Dictyostelium discoideum indicates a low number of sequences with G4-forming potential (249–1055). Therefore, D. discoideum is a perfect model organism to investigate the relationship between the presence of G4s and their biological functions. As a first step in this investigation, we crystallized the dGGGGGAGGGGTACAGGGGTACAGGGG sequence from the putative promoter region of two divergent genes in D. discoideum. According to the crystal structure, this sequence folds into a four-quartet intramolecular antiparallel G4 with two lateral and one diagonal loops. The G-quadruplex …
Synthesis And Characterization Of (Pyno−)2gacl: A Redox-Active Gallium Complex, Jacob M. Kirsh , '17, Audra J. Woodside , '19, B. C. Manor, P. J. Carroll, Paul R. Rablen, Christopher R. Graves
Synthesis And Characterization Of (Pyno−)2gacl: A Redox-Active Gallium Complex, Jacob M. Kirsh , '17, Audra J. Woodside , '19, B. C. Manor, P. J. Carroll, Paul R. Rablen, Christopher R. Graves
Chemistry & Biochemistry Faculty Works
We report the synthesis of a gallium complex incorporating redox-active pyridyl nitroxide ligands. The (pyNO−)2GaCl complex was prepared in 85% yield via a salt metathesis route and was characterized by 1H and 13C NMR spectroscopies, X-ray diffraction, and theory. UV–Vis absorption spectroscopy and electrochemistry were used to access the optical and electrochemical properties of the complex, respectively. Our discussion focuses primarily on a comparison of the gallium complex to the corresponding aluminum derivative and shows that although the complexes are very similar, small differences in the electronic structure of the complexes can be correlated to the identity of the metal.
High-Resolution Three-Dimensional Nmr Structure Of The Kras Proto-Oncogene Promoter Reveals Key Features Of A G-Quadruplex Involved In Transcriptional Regulation, A. Kerkour, J. Marquevielle, S. Ivashchenko, Liliya A. Yatsunyk, J.-L. Mergny, G. F. Salgado
High-Resolution Three-Dimensional Nmr Structure Of The Kras Proto-Oncogene Promoter Reveals Key Features Of A G-Quadruplex Involved In Transcriptional Regulation, A. Kerkour, J. Marquevielle, S. Ivashchenko, Liliya A. Yatsunyk, J.-L. Mergny, G. F. Salgado
Chemistry & Biochemistry Faculty Works
Non-canonical base pairing within guanine-rich DNA and RNA sequences can produce G-quartets, whose stacking leads to the formation of a G-quadruplex (G4). G4s can coexist with canonical duplex DNA in the human genome and have been suggested to suppress gene transcription, and much attention has therefore focused on studying G4s in promotor regions of disease-related genes. For example, the human KRAS proto-oncogene contains a nuclease-hypersensitive element located upstream of the major transcription start site. The KRAS nuclease-hypersensitive element (NHE) region contains a G-rich element (22RT; 5′-AGGGCGGTGTGGGAATAGGGAA-3′) and encompasses a Myc-associated zinc finger-binding site that regulates KRAS transcription. The NEH region …
Effect Of Zinc Cations On The Kinetics Of Supramolecular Assembly And The Chirality Of Porphyrin J-Aggregates, A. Romeo, M. A. Castriciano, R. Zagami, G. Pollicino, L Monsù Scolaro, Robert F. Pasternack
Effect Of Zinc Cations On The Kinetics Of Supramolecular Assembly And The Chirality Of Porphyrin J-Aggregates, A. Romeo, M. A. Castriciano, R. Zagami, G. Pollicino, L Monsù Scolaro, Robert F. Pasternack
Chemistry & Biochemistry Faculty Works
Dilute aqueous solutions of anionic meso-4-sulfonatophenyl-porphyrin (TPPS) extract zinc(ii) ions from glass or quartz surfaces at room temperature and efficiently form the corresponding metal complex (ZnTPPS). The partial or complete formation of ZnTPPS has been probed by UV/Vis spectroscopy and both static and time-resolved fluorescence. The source of zinc(ii) ions has been clearly identified through inductively coupled plasma optical emission spectrometry. The presence of increasing amounts of ZnTPPS slows down the rate of TPPS J-aggregate formation in acid solution. This influences the nucleation step and has a profound impact on the onset of chirality in these species. This evidence indicates …
Investigation Of The Interactions Between Pt(Ii) And Pd(Ii) Derivatives Of 5,10,15,20-Tetrakis (N-Methyl-4-Pyridyl) Porphyrin And G-Quadruplex Dna, Navin C. Sabharwal , '14, O. Mendoza, John Michael Nicoludis , '12, Thomas Ruan , '16, J.-L. Mergny, Liliya A. Yatsunyk
Investigation Of The Interactions Between Pt(Ii) And Pd(Ii) Derivatives Of 5,10,15,20-Tetrakis (N-Methyl-4-Pyridyl) Porphyrin And G-Quadruplex Dna, Navin C. Sabharwal , '14, O. Mendoza, John Michael Nicoludis , '12, Thomas Ruan , '16, J.-L. Mergny, Liliya A. Yatsunyk
Chemistry & Biochemistry Faculty Works
G-quadruplexes are non-canonical DNA structures formed by guanine-rich DNA sequences that are implicated in cancer and aging. Understanding how small molecule ligands interact with quadruplexes is essential both to the development of novel anticancer therapeutics and to the design of new quadruplex-selective probes needed for elucidation of quadruplex biological functions. In this work, UV–visible, fluorescence, and circular dichroism spectroscopies, fluorescence resonance energy transfer (FRET) melting assays, and resonance light scattering were used to investigate how the Pt(II) and Pd(II) derivatives of the well-studied 5,10,15,20-tetrakis(N-methyl-4-pyridyl)porphyrin (TMPyP4) interact with quadruplexes formed by the human telomeric DNA, Tel22, and by the G-rich sequences …
Association Of G-Quadruplex Forming Sequences With Human Mtdna Deletion Breakpoints, D. W. Dong, F. Pereira, Steven Paul Barrett , '13, J. E. Kolesar, K. Cao, J. Damas, Liliya A. Yatsunyk, F. B. Johnson, B. A. Kaufman
Association Of G-Quadruplex Forming Sequences With Human Mtdna Deletion Breakpoints, D. W. Dong, F. Pereira, Steven Paul Barrett , '13, J. E. Kolesar, K. Cao, J. Damas, Liliya A. Yatsunyk, F. B. Johnson, B. A. Kaufman
Chemistry & Biochemistry Faculty Works
Background: Mitochondrial DNA (mtDNA) deletions cause disease and accumulate during aging, yet our understanding of the molecular mechanisms underlying their formation remains rudimentary. Guanine-quadruplex (GQ) DNA structures are associated with nuclear DNA instability in cancer; recent evidence indicates they can also form in mitochondrial nucleic acids, suggesting that these non-B DNA structures could be associated with mtDNA deletions. Currently, the multiple types of GQ sequences and their association with human mtDNA stability are unknown. Results: Here, we show an association between human mtDNA deletion breakpoint locations (sites where DNA ends rejoin after deletion of a section) and sequences with G-quadruplex …
N-Methylmesoporphyrin Ix Fluorescence As A Reporter Of Strand Orientation In Guanine Quadruplexes, Navin C. Sabharwal , '14, V. Savikhin, Joshua R. Turek-Herman , '16, John Michael Nicoludis , '12, V. A. Szalai, Liliya A. Yatsunyk
N-Methylmesoporphyrin Ix Fluorescence As A Reporter Of Strand Orientation In Guanine Quadruplexes, Navin C. Sabharwal , '14, V. Savikhin, Joshua R. Turek-Herman , '16, John Michael Nicoludis , '12, V. A. Szalai, Liliya A. Yatsunyk
Chemistry & Biochemistry Faculty Works
Guanine quadruplexes (GQ) are four-stranded DNA structures formed by guanine-rich DNA sequences. The formation of GQs inhibits cancer cell growth, although the detection of GQs invivo has proven difficult, in part because of their structural diversity. The development of GQ-selective fluorescent reporters would enhance our ability to quantify the number and location of GQs, ultimately advancing biological studies of quadruplex relevance and function. N-methylmesoporphyrin IX (NMM) interacts selectively with parallel-stranded GQs; in addition, its fluorescence is sensitive to the presence of DNA, making this ligand a possible candidate for a quadruplex probe. In the present study, we investigated the effect …
Thioflavin T As A Fluorescence Light-Up Probe For G4 Formation, A. R. De La Faverie, A. Guédin, A. Bedrat, Liliya A. Yatsunyk, J.-L. Mergny
Thioflavin T As A Fluorescence Light-Up Probe For G4 Formation, A. R. De La Faverie, A. Guédin, A. Bedrat, Liliya A. Yatsunyk, J.-L. Mergny
Chemistry & Biochemistry Faculty Works
Thioflavin T (ThT) becomes fluorescent in the presence of the G-quadruplex structure such as that formed by the human telomeric motif. In this report, we extend and generalize these observations and show that this dye may be used as a convenient and specific quadruplex probe. In the presence of most, but not all, G4-forming sequences, we observed a large increase in ThT fluorescence emission, whereas the presence of control duplexes and single strands had a more limited effect on emission. This differential behavior allowed us to design a high-throughput assay to detect G4 formation. Hundreds of different oligonucleotides may be …
G-Ruption: The Third International Meeting On G-Quadruplex And G-Assembly, Liliya A. Yatsunyk, T. M. Bryan, F. B. Johnson
G-Ruption: The Third International Meeting On G-Quadruplex And G-Assembly, Liliya A. Yatsunyk, T. M. Bryan, F. B. Johnson
Chemistry & Biochemistry Faculty Works
A three and a half day conference focusing on nucleic acid structures called G-quadruplexes (G4s) and other guanine-based assemblies was held in Sorrento. Italy (June 28-July 1, 2011) and featured 35 invited talks and over 89 posters. The G-quadruplex field continues to expand at an explosive rate with the emergence of new connections to biology, chemistry, physics, and nanotechnology. Following the trend established by the previous two international G4 meetings, the conference touched upon all these areas and facilitated productive exchanges of ideas between researchers from all over the world.
Interaction Of Human Telomeric Dna With N-Methyl Mesoporphyrin Ix, John Michael Nicoludis , '12, Steven Paul Barrett , '13, J.-L. Mergny, Liliya A. Yatsunyk
Interaction Of Human Telomeric Dna With N-Methyl Mesoporphyrin Ix, John Michael Nicoludis , '12, Steven Paul Barrett , '13, J.-L. Mergny, Liliya A. Yatsunyk
Chemistry & Biochemistry Faculty Works
The remarkable selectivity of N-methyl mesoporphyrin IX (NMM) for G-quadruplexes (GQs) is long known, however its ability to stabilize and bind GQs has not been investigated in detail. Through the use of circular dichroism, UV-visible spectroscopy and fluorescence resonance energy transfer (FRET) melting assay we have shown that NMM stabilizes human telomeric DNA dAG(3)(TTAG(3))(3) (Tel22) and is selective for its parallel conformation to which it binds in 1:1 stoichiometry with a binding constant of similar to 1.0 x 10(5) M-1. NMM does not interact with an antiparallel conformation of Tel22 in sodium buffer and is the second example in the …
Relating Dynamic Protein Interactions Of Metallochaperones With Metal Transfer At The Single-Molecule Level, J. J. Benítez, A. M. Keller, D. L. Huffman, Liliya A. Yatsunyk, A. C. Rosenzweig, P. Chen
Relating Dynamic Protein Interactions Of Metallochaperones With Metal Transfer At The Single-Molecule Level, J. J. Benítez, A. M. Keller, D. L. Huffman, Liliya A. Yatsunyk, A. C. Rosenzweig, P. Chen
Chemistry & Biochemistry Faculty Works
Metallochaperones undertake specific interactions with their target proteins to deliver metal ions inside cells. Understanding how these protein interactions are coupled with the underlying metal transfer process is important, but challenging because they are weak and dynamic. Here we use a nanovesicle trapping scheme to enable single-molecule FRET measurements of the weak, dynamic interactions between the copper chaperone Hahl and the fourth metal binding domain (MBD4) of WDP. By monitoring the behaviors of single interacting pairs, we visualize their interactions in real time in both the absence and the presence of various equivalents of Cu(1+). Regardless of the proteins' metallation …
Rudimentary G-Quadruplex-Based Telomere Capping In Saccharomyces Cerevisiae, J. S. Smith, Q. Chen, Liliya A. Yatsunyk, John Michael Nicoludis , '12, M. S. Garcia, R. Kranaster, S. Balasubramanian, D. Monchaud, M.-P. Teulade-Fichou, L. Abramowitz, D. C. Schultz, F. B. Johnson
Rudimentary G-Quadruplex-Based Telomere Capping In Saccharomyces Cerevisiae, J. S. Smith, Q. Chen, Liliya A. Yatsunyk, John Michael Nicoludis , '12, M. S. Garcia, R. Kranaster, S. Balasubramanian, D. Monchaud, M.-P. Teulade-Fichou, L. Abramowitz, D. C. Schultz, F. B. Johnson
Chemistry & Biochemistry Faculty Works
Telomere capping conceals chromosome ends from exonucleases and checkpoints, but the full range of capping mechanisms is not well defined. Telomeres have the potential to form G-quadruplex (G4) DNA, although evidence for telomere G4 DNA function in vivo is limited. In budding yeast, capping requires the Cdc13 protein and is lost at nonpermissive temperatures in cdc13-1 mutants. Here, we use several independent G4 DNA-stabilizing treatments to suppress cdc13-1 capping defects. These include overexpression of three different G4 DNA binding proteins, loss of the G4 DNA unwinding helicase Sgs1, or treatment with small molecule G4 DNA ligands. In vitro, we show …
Conformations Of A Model Protein Revealed By An Aggregating Cuᴵᴵ Porphyrin: Sensing The Difference, G. De Luca, A. Romeo, L. M. Scolaro, Robert F. Pasternack
Conformations Of A Model Protein Revealed By An Aggregating Cuᴵᴵ Porphyrin: Sensing The Difference, G. De Luca, A. Romeo, L. M. Scolaro, Robert F. Pasternack
Chemistry & Biochemistry Faculty Works
Aggregated t-CuP binds to poly-L-glutamate through supramolecular interactions, revealing itself to be an extremely sensitive probe for the major conformations of the polymeric scaffold.
Experimental Evidence For Self-Similar Structures In The Aggregation Of Porphyrins In Aqueous Solutions, F. Mallamace, N. Micali, S. Trusso, L. M. Scolaro, A. Romeo, A. Terracina, Robert F. Pasternack
Experimental Evidence For Self-Similar Structures In The Aggregation Of Porphyrins In Aqueous Solutions, F. Mallamace, N. Micali, S. Trusso, L. M. Scolaro, A. Romeo, A. Terracina, Robert F. Pasternack
Chemistry & Biochemistry Faculty Works
We have studied the aggregation of the porphyrin t-H₂Pagg in aqueous solution by light scattering. The intensity profile of the elastically scattered light, studied in the exchanged wave-vector range 0.2 ≤ q ≤ 31.4 μ m⁻¹, indicates that the aggregation produces large monodisperse clusters having a fractal structure, and is driven by diffusion-limited aggregation kinetics. Additional measurements performed at different q values confirm such a picture giving a hydrodynamic radius R(H) consistent with the radius of gyration R(g) measured by elastic scattering. This is explained taking into account the q² dependence observed in the mean decay rate of the intensity-intensity …
Aggregation Of Chlorophyll A Probed By Resonance Light Scattering Spectroscopy, J. C. De Paula, J. H. Robblee, Robert F. Pasternack
Aggregation Of Chlorophyll A Probed By Resonance Light Scattering Spectroscopy, J. C. De Paula, J. H. Robblee, Robert F. Pasternack
Chemistry & Biochemistry Faculty Works
We report the resonance light scattering (RLS) spectra of chlorophyll a aggregated in a 9:1 solution of formamide and pH 6.8 phosphate buffer. The aggregate formed after 2 h of mixing, referred to as Chl(469), shows a strong scattering feature at 469 nm (Soret band) and a much weaker feature at 699 nm (Q(y) band). A kinetic investigation confirmed that the aggregation process is cooperative, and also detected one intermediate (Chl(458)) with a strong RLS spectrum but only a weak CD spectrum. We propose that aggregation proceeds via at least three steps: 1) formation of a nucleating species, probably a …
Evidence For An Unusual Kinetic Phenomenon In The Metallation Of Porphyrins, F. González-Vílchez, R. A. Vilaplana, Robert F. Pasternack
Evidence For An Unusual Kinetic Phenomenon In The Metallation Of Porphyrins, F. González-Vílchez, R. A. Vilaplana, Robert F. Pasternack
Chemistry & Biochemistry Faculty Works
Reaction of copper(II) with water soluble porphyrins (H₂porph) in the presence of ethylenediamine shows an unusual and so far unreported kinetic phenomenon that can be explained in terms of supramolecular assembly formation apparently involving all solute species as confirmed via light scattering and conductivity measurements.
Influence Of Dna On The Rate Of Porphyrin Metallation, Robert F. Pasternack, E. J. Gibbs, R. Santucci, Stephanie A. Schaertel , '86, Panayiotis A. Ellinas , '87, Stanley C. Mah , '87
Influence Of Dna On The Rate Of Porphyrin Metallation, Robert F. Pasternack, E. J. Gibbs, R. Santucci, Stephanie A. Schaertel , '86, Panayiotis A. Ellinas , '87, Stanley C. Mah , '87
Chemistry & Biochemistry Faculty Works
Poly(dG–dC)₂ and poly(dA–dT)₂ have marked influences on the rate of insertion of copper(II) into cationic porphyrins reflecting the interaction mode of the porphyrin with the nucleic acid.