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Articles 1 - 13 of 13

Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

Conversion Of Red Fluorescent Protein Into A Bright Blue Probe, Oksana M. Subach, Illia S. Gundorov, Masami Yoshimura, Fedor V. Subach, Jinghang Zhang, David Grunwald, Ekaterina A. Souslova, Dmitriy M. Chudakov, Vladislav V. Verkhusha Nov 2014

Conversion Of Red Fluorescent Protein Into A Bright Blue Probe, Oksana M. Subach, Illia S. Gundorov, Masami Yoshimura, Fedor V. Subach, Jinghang Zhang, David Grunwald, Ekaterina A. Souslova, Dmitriy M. Chudakov, Vladislav V. Verkhusha

David Grünwald

We used a red chromophore formation pathway, in which the anionic red chromophore is formed from the neutral blue intermediate, to suggest a rational design strategy to develop blue fluorescent proteins with a tyrosine-based chromophore. The strategy was applied to red fluorescent proteins of the different genetic backgrounds, such as TagRFP, mCherry, HcRed1, M355NA, and mKeima, which all were converted into blue probes. Further improvement of the blue variant of TagRFP by random mutagenesis resulted in an enhanced monomeric protein, mTagBFP, characterized by the substantially higher brightness, the faster chromophore maturation, and the higher pH stability than blue fluorescent proteins …


Heterogeneous Rotational Diffusion Of A Fluorescent Probe In Lipid Monolayers, Christina M. Othon Aug 2014

Heterogeneous Rotational Diffusion Of A Fluorescent Probe In Lipid Monolayers, Christina M. Othon

Christina M Othon

The rotational correlation time of the lipid probe 1-palmitoyl-2-{6-[(7-nitro-2-1,3-benzoxadiazol-4-yl)amino]hexanoyl}-sn-glycero-3-phosphocholine (NBD-PC) is measured using fluorescence anisotropy for two lipid species. We measure the rotational diffusion in a monolayer of 1,2-Didecanoyl-sn-glycero-3-phosphocholine (DPPC) which displays a phase transition at room temperature from the liquid expanded to the liquid-condensed phase. The constant rotational diffusion of the probe throughout the phase transition reflects the measurement of dynamics in only the liquid-expanded phase. We contrast the dynamic changes during this phase coexistence to the continuous density increase observed in 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) at room temperature. We observe a non-exponential decay of the probe diffusion consistent with heterogeneity …


Characterization Of A Recently Purified Thermophilic Dnase From A Novel Thermophilic Fungus, Kyle Landry, Robert Levin Jul 2014

Characterization Of A Recently Purified Thermophilic Dnase From A Novel Thermophilic Fungus, Kyle Landry, Robert Levin

Kyle S Landry

A newly isolated thermophilic fungus was found to produce a partially inducible extracellular DNase. This manuscript focuses on the characterization of this novel thermophilic DNase in terms of optimal enzyme conditions, molecular weight, and certain kinetic properties. The DNase was found to be inactivated by the presence of EDTA demonstrating its dependence on metal cofactors for activity. Maximum activity occurred at pH 6.0 with no activity at pH 2.0 or 10.0. The optimal temperature for the purified DNase was 65 °C. The thermophilic DNase was found to be an exonuclease with an estimated molecular weight of 56 kDa.


Crystal Structure And Functional Assignment Of Yfau, A Metal Ion Dependent Class Ii Aldolase From Escherichia Coli K12, Dean Rea, Rebecca Hovington, John Rakus, John Gerlt, Vilmos Fu¨Lo¨P, Timothy Bugg, David Roper Jun 2014

Crystal Structure And Functional Assignment Of Yfau, A Metal Ion Dependent Class Ii Aldolase From Escherichia Coli K12, Dean Rea, Rebecca Hovington, John Rakus, John Gerlt, Vilmos Fu¨Lo¨P, Timothy Bugg, David Roper

John F. Rakus

One of the major challenges in the postgenomic era is the functional assignment of proteins using sequence- and structure-based predictive methods coupled with experimental validation. We have used these approaches to investigate the structure and function of theEscherichia coli K-12 protein YfaU, annotated as a putative 4-hydroxy-2-ketoheptane-1,7-dioate aldolase (HpcH) in the sequence databases. HpcH is the final enzyme in the degradation pathway of the aromatic compound homoprotocatechuate. We have determined the crystal structure of apo-YfaU and the Mg2+−pyruvate product complex. Despite greater sequence and structural similarity to HpcH, genomic context suggests YfaU is instead a 2-keto-3-deoxy sugar aldolase like the …


2-Acylamido Analogues Of N-Acetylglucosamine Prime Formation Of Chitin Oligosaccharides By Yeast Chitin Synthase 2, Jacob Gyore, Archana R. Parameswar, Carleigh F. F. Hebbard, Younghoon Oh, Erfei Bi, Alexei V. Demchenko, Neil P. Price, Peter Orlean May 2014

2-Acylamido Analogues Of N-Acetylglucosamine Prime Formation Of Chitin Oligosaccharides By Yeast Chitin Synthase 2, Jacob Gyore, Archana R. Parameswar, Carleigh F. F. Hebbard, Younghoon Oh, Erfei Bi, Alexei V. Demchenko, Neil P. Price, Peter Orlean

Alexei Demchenko

Chitin, a homopolymer of β1,4-linked N-acetylglucosamine (GlcNAc) residues, is a key component of the cell walls of fungi and the exoskeletons of arthropods. Chitin synthases transfer GlcNAc from UDP-GlcNAc to preexisting chitin chains in reactions that are typically stimulated by free GlcNAc. The effect of GlcNAc was probed by using a yeast strain expressing a single chitin synthase, Chs2, by examining formation of chitin oligosaccharides (COs) and insoluble chitin, and by replacing GlcNAc with 2-acylamido analogues of GlcNAc. Synthesis of COs was strongly dependent on inclusion of GlcNAc in chitin synthase incubations, and N,N′-diacetylchitobiose (GlcNAc2) was the major reaction product. …


Molecular Engineering Of Side-Chain Liquid Crystalline Polymers By Living Polymerizations, Coleen Pugh, Alan L. Kiste Apr 2014

Molecular Engineering Of Side-Chain Liquid Crystalline Polymers By Living Polymerizations, Coleen Pugh, Alan L. Kiste

Coleen Pugh

“Living” anionic, cationic, metalloporphyrin and ring-opening metathesis polymerizations have been used to prepare well-defined side-chain liquid crystalline homopolymers, block and graft copolymers and statistical copolymers. This paper analyzes their successes and failures by reviewing the mechanistic aspects and experimental conditions of each type of polymerization, and identifies other classes of mesogenic monomers that could be polymerized in a controlled manner in the future. The emerging structure/property relationships are then identified using well-defined SCLCPs in which only one structural feature is varied while all others remain constant. The thermal transitions of liquid crystalline polymethacrylates, polynorbomenes and poly(viny1 ether)s reach their limiting …


New Multidetector Solution Could Lead To Safer Alternatives To Faulty Silicone Breast Implants, Judit D. Puskas, Geof Wyatt Apr 2014

New Multidetector Solution Could Lead To Safer Alternatives To Faulty Silicone Breast Implants, Judit D. Puskas, Geof Wyatt

Judit E. Puskas

The article discusses the effort of the University of Akron's Department of Chemical and Biomolecular Engineering to pursue research which aims to reduce or eliminate capsular contracture associated with breast implants. It notes that the new multidetector nanotechnology developed by researchers can be better alternative to silicone gel-filled breast implants. It mentions that the new technology can also help in early diagnosis and imaging of breast cancer.


Structural Insights Into The Interaction Between A Potent Anti-Inflammatory Protein, Viral Cc Chemokine Inhibitor (Vcci), And The Human Cc Chemokine, Eotaxin-1, Nai-Wei Kuo, Yong-Guang Gao, Megan S. Schill, Nancy Isern, Cynthia M. Dupureur, Patricia J. Liwang Mar 2014

Structural Insights Into The Interaction Between A Potent Anti-Inflammatory Protein, Viral Cc Chemokine Inhibitor (Vcci), And The Human Cc Chemokine, Eotaxin-1, Nai-Wei Kuo, Yong-Guang Gao, Megan S. Schill, Nancy Isern, Cynthia M. Dupureur, Patricia J. Liwang

Cynthia Dupureur

Chemokines play important roles in the immune system, not only recruiting leukocytes to the site of infection and inflammation but also guiding cell homing and cell development. The soluble poxvirus-encoded protein viral CC chemokine inhibitor (vCCI), a CC chemokine inhibitor, can bind to human CC chemokines tightly to impair the host immune defense. This protein has no known homologs in eukaryotes and may represent a potent method to stop inflammation. Previously, our structure of the vCCI·MIP-1β (macrophage inflammatory protein-1β) complex indicated that vCCI uses negatively charged residues in β-sheet II to interact with positively charged residues in the MIP-1β N …


Development Of A Novel Affinity Membrane Purification System For Deoxyribonuclease, Kyle Landry, Robert Levin Jan 2014

Development Of A Novel Affinity Membrane Purification System For Deoxyribonuclease, Kyle Landry, Robert Levin

Kyle S Landry

A membrane based affinity purification system was developed for the purification of the DNA specific nuclease, DNase I. Single stranded DNA was bound to unmodified polyvinylidene fluoride (PVDF) membranes which were used to purify DNase I from a solution of bovine serum albumin. Using coated membranes, a 6-fold increase in specific activity was achieved with 80 % enzyme recovery. This method provides a simple yet effective way to purify DNase I and can be very useful for the purification of other DNA specific enzymes.


Insights Into The Cation Permeation Pathway Of Channelrhodopsin-2, Robert Dempski, Ryan Richards Dec 2013

Insights Into The Cation Permeation Pathway Of Channelrhodopsin-2, Robert Dempski, Ryan Richards

Robert E. Dempski

Channelrhodopsin-2 (ChR2) is a light-activated, non-selective cation channel endogenous to the green algae Chlamydomonas reinhardtii. The unique properties of ChR2 have made it a useful tool in the field of optogenetics. However, the mechanism of ion conductance is not well resolved. Elucidation of the crystal structure of the channelrhodopsin chimera C1C2 has provided structural insight on the putative ChR2 ion conductance pathway. However, it is not clear how the chimeric structure correlates to ChR2 function.


Purification Of An Inducible Dnase From A Thermophilic Fungus, Kyle Landry, Andrea Vu, Robert Levin Dec 2013

Purification Of An Inducible Dnase From A Thermophilic Fungus, Kyle Landry, Andrea Vu, Robert Levin

Kyle S Landry

The ability to induce an extracellular DNase from a novel thermophilic fungus was studied and the DNAse purified using both traditional and innovative purification techniques. The isolate produced sterile hyphae under all attempted growing conditions, with an average diameter of 2 μm and was found to have an optimal temperature of 45 °C and a maximum of 65 °C. Sequencing of the internal transcribed region resulted in a 91% match with Chaetomium sp., suggesting a new species, but further clarification on this point is needed. The optimal temperature for DNase production was found to be 55 °C and was induced by the …


Purification And Characterization Of Iso-Ribonucleases From A Novel Thermophilic Fungus, Kyle Landry, Robert Levin Dec 2013

Purification And Characterization Of Iso-Ribonucleases From A Novel Thermophilic Fungus, Kyle Landry, Robert Levin

Kyle S Landry

A thermophilic fungus previously isolated from composted horse manure was found to produce extracellular iso-RNases that were purified 127.6-fold using a combination of size exclusion chromatography and a novel affinity membrane purification system. The extent of purification was determined electrophoretically using 4%–15% gradient polyacrylamide gels. RNase activity was dependent on the presence of a metal co-factor with significantly more activity with Zn2+ or Mn2+ than Mg2+. The RNases exhibited maximum activity at both pH 3.0 and pH 7.0 with no activity at pH 2.0 or 10.0. The optimal temperature for the iso-RNase was 70 °C. The …


Intrinsic Delocalization During The Decay Of Excitons In Polymeric Solar Cells, Thomas F. George, W. Chen, D. Jiang, R. Chen, S. Li Dec 2013

Intrinsic Delocalization During The Decay Of Excitons In Polymeric Solar Cells, Thomas F. George, W. Chen, D. Jiang, R. Chen, S. Li

Thomas George

In bulk heterojunction polymer solar cells, external photoexcitation results in localized excitons in the polymer chain. After hot exciton formation and subsequent relaxation, the dipole moment drives the electron to partially transfer to extended orbitals from the original localized ones, leading to self-delocalization. Based on the dynamic fluorescence spectra, the delocalization of excitons is revealed to be an intrinsic property dominated by exciton decay, acting as a bridge for the exciton to diffuse in the polymeric solar cell. The modification of the dipole moment enhances the efficiency of polymer solar cells.