Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 15 of 15

Full-Text Articles in Physical Sciences and Mathematics

Guanidinium–Amino Acid Hydrogen-Bonding Interactions In Protein Crystal Structures: Implications For Guanidinium-Induced Protein Denaturation, Indu Negi, Raman Jangra, Amit Gharu, John F. Trant, Purshotam Sharma Dec 2022

Guanidinium–Amino Acid Hydrogen-Bonding Interactions In Protein Crystal Structures: Implications For Guanidinium-Induced Protein Denaturation, Indu Negi, Raman Jangra, Amit Gharu, John F. Trant, Purshotam Sharma

Chemistry and Biochemistry Publications

In the present work, 86 available high resolution X-ray structures of proteins that contain one or more guanidinium ions (Gdm+) are analyzed for the distribution and nature of noncovalent interactions between Gdm+ and amino-acid residues. A total of 1044 hydrogen-bonding interactions were identified, of which 1039 are N–H⋯O, and five are N–H⋯N. Acidic amino acids are more likely to interact with Gdm+ (46% of interactions, 26% Asp and 20% Glu), followed by Pro (19% of interactions). DFT calculations on the identified Gdm+–amino acid hydrogen-bonded pairs reveal that although Gdm+ interacts primarily with the backbone amides of nonpolar amino acids, Gdm+ …


A Nanodiamond Chemotherapeutic Folate Receptor-Targeting Prodrug With Triggerable Drug Release, Jiangtao Wu, Xiangbin Du, Dongmei Zhang, Jicheng Cui, Xiaoxia Zhang, Xine Duan, John F. Trant, Yingqi Li Nov 2022

A Nanodiamond Chemotherapeutic Folate Receptor-Targeting Prodrug With Triggerable Drug Release, Jiangtao Wu, Xiangbin Du, Dongmei Zhang, Jicheng Cui, Xiaoxia Zhang, Xine Duan, John F. Trant, Yingqi Li

Chemistry and Biochemistry Publications

No abstract provided.


Vitamin E Does Not Disturb Polyunsaturated Fatty Acid Lipid Domains, Mitchell Dipasquale, Michael H.L. Nguyen, Stuart R. Castillo, Isabelle J. Dib, Elizabeth G. Kelley, Drew Marquardt Nov 2022

Vitamin E Does Not Disturb Polyunsaturated Fatty Acid Lipid Domains, Mitchell Dipasquale, Michael H.L. Nguyen, Stuart R. Castillo, Isabelle J. Dib, Elizabeth G. Kelley, Drew Marquardt

Chemistry and Biochemistry Publications

The function of vitamin E in biomembranes remains a prominent topic of discussion. As its limitations as an antioxidant persist and novel functions are discovered, our understanding of the role of vitamin E becomes increasingly enigmatic. As a group of lipophilic molecules (tocopherols and tocotrienols), vitamin E has been shown to influence the properties of its host membrane, and a wealth of research has connected vitamin E to polyunsaturated fatty acid (PUFA) lipids. Here, we use contrast-matched small-angle neutron scattering and differential scanning calorimetry to integrate these fields by examining the influence of vitamin E on lipid domain stability in …


Partial Volumes Of Phosphatidylcholines And Vitamin E: Α-Tocopherol Prefers Disordered Membranes, Mitchell Dipasquale, Michael H.L. Nguyen, Georg Pabst, Drew Marquardt Sep 2022

Partial Volumes Of Phosphatidylcholines And Vitamin E: Α-Tocopherol Prefers Disordered Membranes, Mitchell Dipasquale, Michael H.L. Nguyen, Georg Pabst, Drew Marquardt

Chemistry and Biochemistry Publications

Despite its discovery over 95 years ago, the biological and nutritional roles of vitamin E remain subjects of much controversy. Though it is known to possess antioxidant properties, recent assertions have implied that vitamin E may not be limited to this function in living systems. Through densitometry measurements and small-angle X-ray scattering we observe favorable interactions between α-tocopherol and unsaturated phospholipids, with more favorable interactions correlating to an increase in lipid chain unsaturation. Our data provide evidence that vitamin E may preferentially associate with oxygen sensitive lipids-an association that is considered innate for a viable membrane antioxidant.


The Total Synthesis Of Glycolipids From Streptococcus Pneumoniae And A Re-Evaluation Of Their Immunological Activity**, Seyed Iraj Sadraei, Greg Yousif, S. Maryamdokht Taimoory, Maryam Kosar, Samaneh Mehri, Raghd Alolabi, Emmanuel Igbokwe, Jason Toma, Mir Munir A. Rahim, John F. Trant Jul 2022

The Total Synthesis Of Glycolipids From Streptococcus Pneumoniae And A Re-Evaluation Of Their Immunological Activity**, Seyed Iraj Sadraei, Greg Yousif, S. Maryamdokht Taimoory, Maryam Kosar, Samaneh Mehri, Raghd Alolabi, Emmanuel Igbokwe, Jason Toma, Mir Munir A. Rahim, John F. Trant

Chemistry and Biochemistry Publications

Invariant natural killer (iNK) T cells, Type I iNKTs, are responsible for the production of pro-inflammatory cytokines which induce a systemic immune response. They are distinctive in possessing an semi-invariant T-cell receptor that recognizes glycolipid antigens presented by CD1d, a protein closely related to the class I major histocompatibility complex, conserved across multiple mammalian species in a class of proteins well-renowned for their high degree of polymorphism. This receptor's first potent identified antigen is the α-galactosylceramide, KRN7000, a synthetic glycosphingolipid closely related to those isolated from bacteria that were found on a Japanese marine sponge. A corresponding terrestrial antigen remained …


The Interaction And Orientation Of Peptide Kl4 In Model Membranes, Drew Marquardt, Brad Van Oosten, Maksymilian Dziura, Joanna R. Long, Thad A. Harroun Jul 2022

The Interaction And Orientation Of Peptide Kl4 In Model Membranes, Drew Marquardt, Brad Van Oosten, Maksymilian Dziura, Joanna R. Long, Thad A. Harroun

Chemistry and Biochemistry Publications

We report on the orientation and location of synthetic pulmonary surfactant peptide KL4, (KLLLL)4K, in model lipid membranes. The partitioning depths of selectively deuterated leucine residues within KL4 were determined in DPPC:POPG (4:1) and POPC:POPG (4:1) bilayers by oriented neutron diffraction. These measurements were combined with an NMR-generated model of the peptide structure to determine the orientation and partitioning of the peptide at the lipid–water interface. The results demonstrate KL4 adopting an orientation that interacts with a single membrane leaflet. These observations are consistent with past 2H NMR and EPR studies (Antharam et al., 2009; Turner et al., 2014).


Probing The Link Between Pancratistatin And Mitochondrial Apoptosis Through Changes In The Membrane Dynamics On The Nanoscale, Stuart R. Castillo, Brett W. Rickeard, Mitchell Dipasquale, Michael H.L. Nguyen, Aislyn Lewis-Laurent, Milka Doktorova, Batuhan Kav, Markus S. Miettinen, Michihiro Nagao, Elizabeth G. Kelley, Drew Marquardt Jun 2022

Probing The Link Between Pancratistatin And Mitochondrial Apoptosis Through Changes In The Membrane Dynamics On The Nanoscale, Stuart R. Castillo, Brett W. Rickeard, Mitchell Dipasquale, Michael H.L. Nguyen, Aislyn Lewis-Laurent, Milka Doktorova, Batuhan Kav, Markus S. Miettinen, Michihiro Nagao, Elizabeth G. Kelley, Drew Marquardt

Chemistry and Biochemistry Publications

Pancratistatin (PST) is a natural antiviral alkaloid that has demonstrated specificity toward cancerous cells and explicitly targets the mitochondria. PST initiates apoptosis while leaving healthy, noncancerous cells unscathed. However, the manner by which PST induces apoptosis remains elusive and impedes the advancement of PST as a natural anticancer therapeutic agent. Herein, we use neutron spin-echo (NSE) spectroscopy, molecular dynamics (MD) simulations, and supporting small angle scattering techniques to study PST's effect on membrane dynamics using biologically representative model membranes. Our data suggests that PST stiffens the inner mitochondrial membrane (IMM) by being preferentially associated with cardiolipin, which would lead to …


Naphthalene-Functionalized Resorcinarene As Selective, Fluorescent Self-Quenching Sensor For Kynurenic Acid†, Anna Karle, Kwaku Twum, Noorhan Sabbagh, Alise Haddad, S. Maryamdokht Taimoory, Małgorzata M. Szczęśniak, Evan Trivedi, John F. Trant, Ngong Kodiah Beyeh Apr 2022

Naphthalene-Functionalized Resorcinarene As Selective, Fluorescent Self-Quenching Sensor For Kynurenic Acid†, Anna Karle, Kwaku Twum, Noorhan Sabbagh, Alise Haddad, S. Maryamdokht Taimoory, Małgorzata M. Szczęśniak, Evan Trivedi, John F. Trant, Ngong Kodiah Beyeh

Chemistry and Biochemistry Publications

Kynurenic acid is a by-product of tryptophan metabolism in humans, with abnormal levels indicative of disease. There is a need for water-soluble receptors that selectively bind kynurenic acid, allowing for detection and quantification. We report here the high-affinity binding of kynurenic acid in aqueous media to a resorcinarene salt receptor decorated with four flexible naphthalene groups at the upper rim. Experimental results from 1H NMR, isothermal titration calorimetry, and electronic absorption and fluorescence spectroscopies all support high-affinity binding and selectivity for kynurenic acid over tryptophan. The measured binding constant (K = 1.46 ± 0.21 × 105 M−1) is one …


Effect Of Mono-Vacant Defects On The Adsorption Properties Of Deep Eutectic Solvents Onto Hexagonal Boron-Nitride Nanoflakes, Mehdi Shakourian-Fard, S. Maryamdokht Taimoory, Hamid Reza Ghenaatian, Ganesh Kamath, John F. Trant Mar 2022

Effect Of Mono-Vacant Defects On The Adsorption Properties Of Deep Eutectic Solvents Onto Hexagonal Boron-Nitride Nanoflakes, Mehdi Shakourian-Fard, S. Maryamdokht Taimoory, Hamid Reza Ghenaatian, Ganesh Kamath, John F. Trant

Chemistry and Biochemistry Publications

Hexagonal boron nitride is a promising material for a variety of electronic, optical, and material science applications. Both the synthesis of the material through exfoliation, and its various applications almost inevitably require its solvation. Deep eutectic solvents (DES) are extremely useful solvents for these types of applications due to their non-volatility, inflammability, biocompatibility, and reasonable cost. There are many different deep eutectic solvents available, and their suitability for any given application is particularly dependent on the specific of their structure. DES have been examined computationally for use with boron nitride, but these calculations use idealized, perfect boron nitride sheets instead …


Flexible And Printed Electronics: A Transition In Leadership - Reflecting On Our Successes And Looking Forward To The Future, Tricia Breen Carmichael, Ronald Österbacka Mar 2022

Flexible And Printed Electronics: A Transition In Leadership - Reflecting On Our Successes And Looking Forward To The Future, Tricia Breen Carmichael, Ronald Österbacka

Chemistry and Biochemistry Publications

No abstract provided.


Giving Preparative Thin-Layer Chromatography Some Tender ­Loving Care, John J. Hayward, Lavleen Mader, John F. Trant Feb 2022

Giving Preparative Thin-Layer Chromatography Some Tender ­Loving Care, John J. Hayward, Lavleen Mader, John F. Trant

Chemistry and Biochemistry Publications

Preparative thin-layer chromatography (prepTLC) is a commonly used method of purification suitable for small-scale reactions. However, descriptions of the preferred methodology to load, run, and recover samples from prepTLC are non-standard and varied, making it part of the ‘hidden curriculum’ of laboratory techniques. In this article we report on the simple, cost-effective methods we use to load and collect samples from a plate, which enhance the convenience, speed, and precision of this technique.


Fabrication And Characterization Of Autonomously Self-Healable And Stretchable Soft Microfluidics, Hualong Wang, Susanna Vu, Julia Pignanelli, Tamer Abdel Fatah, John F. Trant, Sara Mahshid, Simon Rondeau-Gagné, Mohammed Jalal Ahamed Feb 2022

Fabrication And Characterization Of Autonomously Self-Healable And Stretchable Soft Microfluidics, Hualong Wang, Susanna Vu, Julia Pignanelli, Tamer Abdel Fatah, John F. Trant, Sara Mahshid, Simon Rondeau-Gagné, Mohammed Jalal Ahamed

Chemistry and Biochemistry Publications

In this paper, a novel self-healable and stretchable microfluidics system for next generation wearable lab-on-a-chip is presented. An imine-based precursor with various metal sources (Co(II), Fe(II), and Zn(II)) is used for the development of an intrinsically autonomous self-healing microfluidic device. Microfluidics fabrication is performed on the self-healing substrate layer using a mold transfer method. The mechanical properties of the resulting layer are evaluated using tensile strain pull testing. Microfluidic characteristics including fluid flow, wettability, leak, and fluorescence compatibility are investigated to understand its performance in classical microfluidic applications. The new microfluidic devices are also characterized using scanning-electron microscopy to evaluate …


Identification Of Alternative Protein Targets Of Glutamate-Ureido-Lysine Associated With Psma Tracer Uptake In Prostate Cancer Cells, Martin K. Bakht, John J. Hayward, Farsheed Shahbazi-Raz, Magdalena Skubal, Ryo Tamura, Keith F. Stringer, Daniel Meister, Varadha Balaji Venkadakrishnan, Hui Xue, Adam Pillon, Mathew Stover, Adam Tronchin, Bre Anne Fifield, Lavleen Mader, Sheng Yu Ku, Gi Jeong Cheon, Keon Wook Kang, Yuzhuo Wang, Xuesen Dong, Himisha Beltran, Jan Grimm, Lis A. Porter, John F. Trant Jan 2022

Identification Of Alternative Protein Targets Of Glutamate-Ureido-Lysine Associated With Psma Tracer Uptake In Prostate Cancer Cells, Martin K. Bakht, John J. Hayward, Farsheed Shahbazi-Raz, Magdalena Skubal, Ryo Tamura, Keith F. Stringer, Daniel Meister, Varadha Balaji Venkadakrishnan, Hui Xue, Adam Pillon, Mathew Stover, Adam Tronchin, Bre Anne Fifield, Lavleen Mader, Sheng Yu Ku, Gi Jeong Cheon, Keon Wook Kang, Yuzhuo Wang, Xuesen Dong, Himisha Beltran, Jan Grimm, Lis A. Porter, John F. Trant

Chemistry and Biochemistry Publications

Prostate-specific membrane antigen (PSMA) is highly overexpressed in most prostate cancers and is clinically visualized using PSMA-specific probes incorporating glutamate-ureido-lysine (GUL). PSMA is effectively absent from certain high-mortality, treatment-resistant subsets of prostate cancers, such as neuroendocrine prostate cancer (NEPC); however, GUL-based PSMA tracers are still reported to have the potential to identify NEPC metastatic tumors. These probes may bind unknown proteins associated with PSMA-suppressed cancers. We have identified the up-regulation of PSMA-like aminopeptidase NAALADaseL and the metabotropic glutamate receptors (mGluRs) in PSMA-suppressed prostate cancers and find that their expression levels inversely correlate with PSMA expression and are associated with GUL-based …


Identifying Membrane Lateral Organization By Contrast-Matched Small Angle Neutron Scattering, Mitchell Dipasquale, Michael H.L. Nguyen, Stuart R. Castillo, Frederick A. Heberle, Drew Marquardt Jan 2022

Identifying Membrane Lateral Organization By Contrast-Matched Small Angle Neutron Scattering, Mitchell Dipasquale, Michael H.L. Nguyen, Stuart R. Castillo, Frederick A. Heberle, Drew Marquardt

Chemistry and Biochemistry Publications

Lipid domains in model membranes are routinely studied to provide insight into the physical interactions that drive raft formation in cellular membranes. Using small angle neutron scattering, contrast-matching techniques enable the detection of lipid domains ranging from tens to hundreds of nanometers which are not accessible to other techniques without the use of extrinsic probes. Here, we describe a probe-free experimental approach and model-free analysis to identify lipid domains in freely floating vesicles of ternary phase separating lipid mixtures.


Influence Of Ceramide On Lipid Domain Stability Studied With Small-Angle Neutron Scattering: The Role Of Acyl Chain Length And Unsaturation, Mitchell Dipasquale, Tye G. Deering, Dhimant Desai, Arun K. Sharma, Shantu Amin, Todd E. Fox, Mark Kester, John Katsaras, Drew Marquardt, Frederick A. Heberle Jan 2022

Influence Of Ceramide On Lipid Domain Stability Studied With Small-Angle Neutron Scattering: The Role Of Acyl Chain Length And Unsaturation, Mitchell Dipasquale, Tye G. Deering, Dhimant Desai, Arun K. Sharma, Shantu Amin, Todd E. Fox, Mark Kester, John Katsaras, Drew Marquardt, Frederick A. Heberle

Chemistry and Biochemistry Publications

Ceramides and diacylglycerols are groups of lipids capable of nucleating and stabilizing ordered lipid domains, structures that have been implicated in a range of biological processes. Previous studies have used fluorescence reporter molecules to explore the influence of ceramide acyl chain structure on sphingolipid-rich ordered phases. Here, we use small-angle neutron scattering (SANS) to examine the ability of ceramides and diacylglycerols to promote lipid domain formation in the well-characterized domain- forming mixture DPPC/DOPC/cholesterol. SANS is a powerful, probe-free technique for interrogating membrane heterogeneity, as it is differentially sensitive to hydrogen's stable isotopes protium and deuterium. Specifcally, neutron contrast is generated …