• NMR CBEC
  • OSU CBEC
  • CBEC Lab

Aggregator

Cytotoxic and non-cytotoxic cardiac glycosides isolated from the combined flowers, leaves, and twigs of Streblus asper

4 years 2 months ago
A new non-cytotoxic [(+)-17β-hydroxystrebloside (1)] and two known cytotoxic [(+)-3'-de-O-methylkamaloside (2) and (+)-strebloside (3)] cardiac glycosides were isolated and identified from the combined flowers, leaves, and twigs of Streblus asper collected in Vietnam, with the absolute configuration of 1 established from analysis of its ECD and NMR spectroscopic data and confirmed by computational ECD calculations. A new 14,21-epoxycardanolide (3a) was synthesized from 3 that was treated with...
Yulin Ren

Cytotoxic and non-cytotoxic cardiac glycosides isolated from the combined flowers, leaves, and twigs of Streblus asper

4 years 2 months ago
A new non-cytotoxic [(+)-17β-hydroxystrebloside (1)] and two known cytotoxic [(+)-3'-de-O-methylkamaloside (2) and (+)-strebloside (3)] cardiac glycosides were isolated and identified from the combined flowers, leaves, and twigs of Streblus asper collected in Vietnam, with the absolute configuration of 1 established from analysis of its ECD and NMR spectroscopic data and confirmed by computational ECD calculations. A new 14,21-epoxycardanolide (3a) was synthesized from 3 that was treated with...
Yulin Ren

Meeting – Jan 21st @ 5:30pm

4 years 2 months ago
1. Dr. Ralph Tobias, Hummon Group “Developing a Drug Screening Platform: MALDI-Mass Spectrometry Imaging of Paper-Based Cultures” 2. Ms. Haley Chatelaine, Kopec Group “A Targeted and Untargeted LC-MS Approach to Determining Postprandial Vitamin A&D and Lipid Levels in Metabolic Syndrome versus Healthy Subjects” Date: January 21st Time: 5:30 PM Place: 105 BRT
hall.1443

Localising occult prostate cancer metastasis with advanced imaging techniques (LOCATE trial): a prospective cohort, observational diagnostic accuracy trial investigating whole-body magnetic resonance imaging in radio-recurrent prostate cancer

4 years 4 months ago
BACKGROUND: Accurate whole-body staging following biochemical relapse in prostate cancer is vital in determining the optimum disease management. Current imaging guidelines recommend various imaging platforms such as computed tomography (CT), Technetium 99 m (^(99m)Tc) bone scan and ^(18)F-choline and recently ^(68)Ga-PSMA positron emission tomography (PET) for the evaluation of the extent of disease. Such approach requires multiple hospital attendances and can be time and resource intensive....
Sola Adeleke

Meeting – Nov 26th @ 5:30pm

4 years 4 months ago
1. Dr. Djawed Bennouna, Kopec Research Group, OSU “The Effects of Omega-3 Supplementation on the Brain Lipids after Chemotherapy” 2. Dr. Dmytro Kulyk, Badu Research Group, OSU “High-Throughput Mass Spectrometry Platform for Gas-Phase Reaction Screening under Ambient Conditions” Date: November 26 Time: 5:30 PM Place: 105 BRT
hall.1443

Extreme Nonuniform Sampling for Protein NMR Dynamics Studies in Minimal Time

4 years 6 months ago
NMR spectroscopy is an extraordinarily rich source of quantitative dynamics of proteins in solution using spin relaxation or chemical exchange saturation transfer (CEST) experiments. However, ^(15)N-CEST measurements require prolonged multidimensional, so-called pseudo-3D HSQC experiments where the pseudo dimension is a radio frequency offset Δω of a weak ^(15)N saturation field. Nonuniform sampling (NUS) approaches have the potential to significantly speed up these measurements, but they also...
Gregory Jameson

Extreme Nonuniform Sampling for Protein NMR Dynamics Studies in Minimal Time

4 years 6 months ago
NMR spectroscopy is an extraordinarily rich source of quantitative dynamics of proteins in solution using spin relaxation or chemical exchange saturation transfer (CEST) experiments. However, ^(15)N-CEST measurements require prolonged multidimensional, so-called pseudo-3D HSQC experiments where the pseudo dimension is a radio frequency offset Δω of a weak ^(15)N saturation field. Nonuniform sampling (NUS) approaches have the potential to significantly speed up these measurements, but they also...
Gregory Jameson

Meeting – Sept 24th @ 5:30PM

4 years 6 months ago
Topic: Thermal ionization mass spectrometry methods and applications in the earth and ocean sciences Overview by Prof. Elizabeth Griffith, School of Earth Sciences, OSU Application by Ms. Samantha Carter, Griffith Research Group, OSU Date: September 24 Time: 5:30 PM Place: JAMES B050 (460 W. 10TH Ave)
hall.1443

Don’t miss OMSMS 2019!

4 years 6 months ago
Please join us for the 3rd Annual Ohio Mass Spectrometry and Metabolomics Symposium (OMSMS) to be held at the Blackwell Inn and Pfahl Conference Center at The Ohio State University in Columbus, Ohio, on October 1-2, 2019. Invited keynote and plenary presentations: Connecting the World’s Mass Spectrometry Data to Understand the Chemistry of Life — a Big […]
hall.1443

Functional protein dynamics on uncharted time scales detected by nanoparticle-assisted NMR spin relaxation

4 years 7 months ago
Protein function depends critically on intrinsic internal dynamics, which is manifested in distinct ways, such as loop motions that regulate protein recognition and catalysis. Under physiological conditions, dynamic processes occur on a wide range of time scales from subpicoseconds to seconds. Commonly used NMR spin relaxation in solution provides valuable information on very fast and slow motions but is insensitive to the intermediate nanosecond to microsecond range that exceeds the protein...
Mouzhe Xie

Functional protein dynamics on uncharted time scales detected by nanoparticle-assisted NMR spin relaxation

4 years 7 months ago
Protein function depends critically on intrinsic internal dynamics, which is manifested in distinct ways, such as loop motions that regulate protein recognition and catalysis. Under physiological conditions, dynamic processes occur on a wide range of time scales from subpicoseconds to seconds. Commonly used NMR spin relaxation in solution provides valuable information on very fast and slow motions but is insensitive to the intermediate nanosecond to microsecond range that exceeds the protein...
Mouzhe Xie

Meeting – August 27th @ 5:30PM

4 years 7 months ago
Mr. Taghi Sahraeian, Badu Research Group, OSU “Droplet Imbibition Enables Non-Equilibrium Interfacial Reactions in Charged Microdroplets” Date: August 27th Time: 5:30 PM Place: 105 BRT COH-MSDG – Central Ohio (OH) Mass Spectrometry Discussion Group
hall.1443

Seminar – August 20th 4:00PM – “Deciphering Proteins with Unknown Functions in Plants using Top-Down and Native Mass Spectrometry Techniques”

4 years 7 months ago
Mowei Zhou will present a seminar while visiting us from Pacific Northwest National Laboratory next week: “Deciphering Proteins with Unknown Functions in Plants using Top-Down and Native Mass Spectrometry Techniques” Tuesday, August 20, 2019 4:00 pm BRT 105 Mass spectrometry (MS) has been widely used in proteomics applications for identifying and quantifying proteins in biological […]
hall.1443

Metabolic Regulation of Glycolysis and AMP Activated Protein Kinase Pathways during Black Raspberry-Mediated Oral Cancer Chemoprevention

4 years 8 months ago
Oral cancer is a public health problem with an incidence of almost 50,000 and a mortality of 10,000 each year in the USA alone. Black raspberries (BRBs) have been shown to inhibit oral carcinogenesis in several preclinical models, but our understanding of how BRB phytochemicals affect the metabolic pathways during oral carcinogenesis remains incomplete. We used a well-established rat oral cancer model to determine potential metabolic pathways impacted by BRBs during oral carcinogenesis. F344...
Thomas J Knobloch

Metabolic Regulation of Glycolysis and AMP Activated Protein Kinase Pathways during Black Raspberry-Mediated Oral Cancer Chemoprevention

4 years 8 months ago
Oral cancer is a public health problem with an incidence of almost 50,000 and a mortality of 10,000 each year in the USA alone. Black raspberries (BRBs) have been shown to inhibit oral carcinogenesis in several preclinical models, but our understanding of how BRB phytochemicals affect the metabolic pathways during oral carcinogenesis remains incomplete. We used a well-established rat oral cancer model to determine potential metabolic pathways impacted by BRBs during oral carcinogenesis. F344...
Thomas J Knobloch

Seminar – June 25th 10:00-11:00am “Uncovering Antimicrobial Peptide Interactions in Lipid Nanodiscs by Native MS”

4 years 9 months ago
A special seminar will be presented by Dr. Michael T. Marty (University of Arizona) on Uncovering Antimicrobial Peptide Interactions in Lipid Nanodiscs by Native MS. Tuesday, June 25th 10:00-11:00 am BRT 105 Research in the Marty lab is focused on developing mass spectrometry methods to study the structure and biophysics of membrane proteins. Working at […]
hall.1443

Structural analysis of phospholipase A2 from functional perspective. 1. Functionally relevant solution structure and roles of the hydrogen-bonding network.

4 years 10 months ago
Icon for American Chemical Society Related Articles

Structural analysis of phospholipase A2 from functional perspective. 1. Functionally relevant solution structure and roles of the hydrogen-bonding network.

Biochemistry. 1999 Mar 09;38(10):2909-18

Authors: Yuan C, Byeon IJ, Li Y, Tsai MD

Abstract
Bovine pancreatic phospholipase A2 (PLA2), a small (13.8 kDa) Ca2+-dependent lipolytic enzyme, is rich in functional and structural character. In an effort to examine its detailed structure-function relationship, we determined its solution structure by multidimensional nuclear magnetic resonance (NMR) spectroscopy at a functionally relevant pH. An ensemble of 20 structures generated has an average root-mean-square deviation (RMSD) of 0.62 +/- 0.08 A for backbone (N, Calpha, C) atoms and 0.98 +/- 0.09 A for all heavy atoms. The overall structure shows several notable differences from the crystal structure: the first three residues at the N-terminus, the calcium-binding loop (Y25-T36), and the surface loop (V63-N72) appear to be flexible; the alpha-helical conformation of helix B (E17-F22) is absent; helix D appears to be shorter (D59-V63 instead of D59-D66); and the hydrogen-bonding network is less defined. These differences were analyzed in relation to the function of PLA2. We then further examined the H-bonding network, because its functional role or even its existence in solution has been in dispute recently. Our results show that part of the H-bonding network (the portion away from N-terminus) clearly exists in solution, as evidenced by direct observation (at 11.1 ppm) of a strong H-bond between Y73 and D99 and an implicated interaction between D99 and H48. Analyses of a series of mutants indicated that the existence of the Y73.D99 H-bond correlates directly with the conformational stability of the mutant. Loss of this H-bond results in a loss of 2-3 kcal/mol in the conformational stability of PLA2. The unequivocal identification and demonstration of the structural importance of a specific hydrogen bond, and the magnitude of its contribution to conformational stability, are uncommon to the best of our knowledge. Our results also suggest that, while the D99.H48 catalytic diad is the key catalytic machinery of PLA2, it also helps to maintain conformational integrity.

PMID: 10074343 [PubMed - indexed for MEDLINE]

Yuan C, Byeon IJ, Li Y, Tsai MD