The anisotropic motion of tightly bound waters of hydration in bovine nuchal ligament elastin has been studied by deuterium Double Quantum Filtered (DQF) NMR. The experiments have allowed for a direct measurement of the degree of anisotropy within pores of elastin over a time scale ranging from 100 micros to 30 ms, corresponding to a tortuous spatial displacement ranging from 0.2 to 7 microm. We studied the anisotropic motion of deuterium nuclei in D2O hydrated elastin over a temperature of -15 degrees C to 37 degrees C and in solvents with varying dielectric constants. Our experimental measurements of the residual quadrupolar interaction as a function of temperature are correlated to the existing notion of hydrophobic collapse near 20 degrees C.
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http://dx.doi.org/10.1016/j.jmr.2010.04.007 | DOI Listing |
J Org Chem
January 2025
Key Laboratory of Chemistry and Engineering of Forest Products, State Ethnic Affairs Commission, Guangxi Key Laboratory of Chemistry and Engineering of Forest Products, Guangxi Collaborative Innovation Center for Chemistry and Engineering of Forest Products, Laboratory of Optic-electric Chemo/Biosensing and Molecular Recognition, Education Department of Guangxi Zhuang Autonomous Region, Guangxi Minzu University, Nanning 530006, China.
A regioselective [3 + 2] annulation of β,γ-alkynyl-α-ketimino esters with 1,3-dicarbonyls is disclosed. A series of -selective dihydrofurans bearing an exocyclic double bond and a quaternary carbon center are accessed without the usage of base. Control and deuterium-labeling experiments have been investigated to probe into the reaction mechanism.
View Article and Find Full Text PDFMetabolites
January 2025
Institute of Toxicology, Core Unit Proteomics, Hannover Medical School, 30623 Hannover, Germany.
Charge-free gaseous molecules labeled with deuterium H (D) atoms elute earlier than their protium-analogs H (H) from most stationary GC phases. This effect is known as the chromatographic H/D isotope effect (IE) and can be calculated by dividing the retention times () of the protiated ( ) to those of the deuterated () analytes: IE = /. Analytes labeled with C, N or O have almost identical retention times and lack a chromatographic isotope effect.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, TX 75080.
J Am Soc Mass Spectrom
December 2024
Institute for Bioscience and Biotechnology Research, National Institute of Standards and Technology and the University of Maryland, College Park, Rockville, Maryland 20850, United States.
Sample carryover is a common problem in hydrogen-deuterium exchange mass spectrometry, particularly because immobilized protease columns cannot withstand the high organic solvent concentrations typically used in liquid chromatography-mass spectrometry (LC-MS) for cleaning. Conventional cleaning methods using injections of guanidine HCl still suffer from carryover and may require four blanks after each sample run to fully remove carryover. We have implemented an additional LC pump to deliver customized wash solutions to protease and enzyme columns, and the associated LC capillaries to eliminate carryover.
View Article and Find Full Text PDFBiochemistry
January 2025
Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland 21201-1180, United States.
Ran-binding domain-containing protein 2 (ZRANB2) is a zinc finger (ZF) protein that plays a key role in alternative splicing. ZRANB2 is composed of two ZF domains that contain four invariant cysteine residues per domain. ZRANB2 binds RNA targets that contain AGGUAA sequence motifs.
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