-
Ester hydrolysis of calcein-AM in a lipid bilayer demonstrates the concept of lipozyme catalysis
Kiran Kumar – @KiranKumar86269
Lipids are not typically thought to catalyze biological reactions, but evidence shows that certain lipid aggregates can speed up chemical reactions in synthetic organic chemistry. We demonstrate the potential for the hydrophobic region of a lipid bilayer to provide an environment suitable for catalysis as lipozyme. We demonstrate this concept by the ester hydrolysis of calcein-AM to produce calcein as a fluorescent product, Which is a widely used assay for esterase activity in cells. The reaction product was characterized by microscopy and 1H-NMR measurements. Overall, we explore the implications of considering lipid aggregates as catalytic entities
-
Exploring Adiabatic Inversion for Integrated Solid Effect
Mayur Manoj Jhamnani – @mayur_jhamnani
We explore the use of adiabatic inversion techniques to enhance the integrated solid effect (ISE). By carefully controlling the system parameters, we demonstrate how adiabatic inversion can be leveraged to improve the efficiency of polarization transfer via ISE. The findings have important implications for the development of triplet-DNP.
Leave a Reply
-
Fluorine-19 Decoupling in Solid-state NMR
Zeba Qadri – @ZebaQadri92778
Fluorine-19 solid-state NMR offers significant advantages in pharmaceutical and material studies, providing atomic-level insights into structure and dynamics due to its high sensitivity and abundance. Despite its potential, F-19 decoupling remains challenging due to high chemical shift anisotropy. This presentation would bring forth the issues associated with f-19 decoupling while applying the traditional decoupling strategies and possible solutions to overcome it and enhance their efficacy towards spectral resolution.
Leave a Reply
-
From Rigid to Flexible: Impact of Macrocycle Loss on Tolaasin’s Backbone Dynamics and Activity
Durga Prasad
In this project, we investigate the impact of macrocycle loss on tolaasin activity. Tolaasin, a Cyclic Lipopeptide (CLiP) from Pseudomonas tolaasii, plays a critical role in causing brown blotch disease in mushrooms. Its 18-amino acid sequence features an N-terminal lipid tail and a macrocycle formed via an ester bond. Tolaasin exhibits inhibitory action against fungal and Gram-positive bacteria, underscoring its significance. Studies have shown that hydrolysing the ester bond, potentially opening the macrocycle, can detoxify tolaasin, highlighting the macrocycle’s role in tolaasin’s function. Understanding how specific structural changes alter membrane interactions is crucial for developing novel therapeutics and biocontrol agents.
Our approach involves studying hydrolysed tolaasin in parallel with the native molecule in SDS micelles using NMR spectroscopy. To enable advanced multidimensional structural analysis, we first produce 15N isotope-enriched tolaasin by cultivating the producing bacterium on a minimal medium supplemented with suitable labeled isotopically enriched precursors. Subsequently, isotopically enriched hydrolyzed form was synthesized through controlled alkaline hydrolysis.
A comprehensive analysis, including full resonance assignment and 15N R1, R2, and het-nOe experiments, allows us to investigate peptide backbone dynamics. The order parameters (S2) derived from model-free analysis of relaxation data provide insights into molecular motions occurring on a nanosecond to picosecond timescale. By employing reduced spectral density mapping at Jω0, JωN, and Jω0.87H, we distinguish residues with distinct rigidity and flexibility profiles in both forms of tolaasin. Furthermore, NH R1 rates are determined both in the absence and presence of a soluble paramagnetic relaxation agent. This facilitates mapping the PRE wave of tolaasin, extracting tilt and azimuth angles, and enabling the mapping of helix orientations. Our findings indicate that the opening up of the macrocycle results in a partial loss of peptide backbone rigidity, leading to involvement in microsecond dynamics by later exocyclic residues.Leave a Reply
-
Functional insight and Mechanistic Study of UBA domain of E2-25K in Lys-48 Ubiquitin Chain Elongation
Gajendra Singh
E2-25K (Ube2K) is a ubiquitin-conjugating enzyme that can only synthesize the K48(Lys-48) ubiquitin chain. All ubiquitin E2s have a conserved catalytic ubiquitin-conjugating domain (UBC), whereas E2-25K is the only enzyme that contains additional C-terminal ubiquitin association domain (UBA). We investigated the function of UBA domain in K48 chain elongation. NMR based results suggest that UBA domain provides the binding surface to ubiquitin during the chain elongation. It also holds the di ubiquitin (Ub 2) with different affinity to proximal and distal Ub units. We showed that the UBA domain expedites the polyubiquitin (K48) chain formation. Fluorescent polarization and mutational studies indicated that the UBA domain increases the K48 chain processivity. However, the activity is dependent upon the Ub chain length. Gel-based kinetics results also manifest the function UBA domain in polyubiquitin chain and the results evident that the rate reduces, drastically with truncated UBA domain.
Leave a Reply
-
Hot and bothered: understanding the metabolic effects of heat stress in feedlot cattle using NMR-based metabolomics and clinical biochemistry
Alexandra Gloria – @_AGloria
Feedlot cattle are crucial to Australia’s livestock industry, supplying beef for domestic and export markets. High summer temperatures and humidity increase heat stress vulnerability, impacting growth, productivity, and welfare. We use NMR-based metabolomics and clinical biochemistry to understand the metabolic effects of heat stress to help mitigate its impact.
Leave a Reply
-
How Do We Teach Nuclear Magnetic Resonance?
Scott Carnahan – @scarnaha_smumn
I wish to start a conversation on how NMR is taught. I’ll discuss how we approach education of NMR at my University, and solicit input from the community on how NMR is taught elsewhere. As NMR is a significantly important technique, how we teach our students NMR is likewise vital.
Leave a Reply
-
Hunting for 15N DNP in liquids at 14 T
Natalie Ibbetson – @Natalieeibby
15N-DNP has been proven to work up to only 5 T, while other nuclei (13C, 31P) show enhancements up to 14.1 T. Here we show preliminary experiments conducted at 14.1 T on a solution of 15N-aniline doped with BDPA radical and numerical simulation of electron-nuclear hyperfine coupling.
Leave a Reply
-
Identify the initial pinning sites of tau to seeding-competent fibrils and the role of structural water
Chung-Ta Han
We interrogate the key residue(s) that initiate the pinning of soluble Tau onto existing fibril active ends by tracking the time evolution of 1H-15N correlation spectra along the fibril seeding process of a tau construct composed of 19 amino acids.
Leave a Reply
-
In Situ Solid-State NMR Deciphering Dehydration Intermediates on TiO2 facets
Wenda Hu – @WendaHu1
We used in situ 13𝐶-1𝐻 CP and 1𝐻 NMR to identify dehydration intermediates on TiO₂ facets. A water-isopropoxide complex on TiO₂(001) and a water-isopropanol complex on TiO₂(101) explain different dehydration rates, crucial for understanding biomass conversion mechanisms.
Leave a Reply
-
Journey into the essence of red beers with NMR metabolomics
Plamen Chorbadzhiev – @NMR_P_Ch_0359
This research is aimed at studying the chemical profile of 5 styles of Amber/Red beers. 1H NMR spectra were obtained and over 50 chemical compounds were identified and quantified, with further application of chemometric methods to successfully distinguish the styles.
Leave a Reply
-
Magic NOVEL: Suppressing Electron-Electron Coupling Effects in Pulsed DNP
Amaria Javed
Dynamic nuclear polarization (DNP) boosts NMR sensitivity but suffers from electron-electron (e-e) interactions, reducing polarization transfer efficiency. We propose the Magic-NOVEL sequence to counteract these effects. Evaluating Lee-Goldburg NOVEL sequences, our theoretical and simulation results show enhanced electron-to-nucleus polarization transfer by weakening e-e interactions, improving DNP efficiency.
Leave a Reply
Leave a Reply