Author
David E. Wemmer
Other affiliations: University of Southern California, Lawrence Berkeley National Laboratory, California Institute of Technology ...read more
Bio: David E. Wemmer is an academic researcher from University of California, Berkeley. The author has contributed to research in topics: Nuclear magnetic resonance spectroscopy & Protein structure. The author has an hindex of 75, co-authored 307 publications receiving 19499 citations. Previous affiliations of David E. Wemmer include University of Southern California & Lawrence Berkeley National Laboratory.
Papers published on a yearly basis
Papers
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TL;DR: The synthesis, proof of structure, and the absorption and fluorescence properties of two new unsymmetrical cyanine dyes, thiazole orange dimer and oxazole yellow dimer are reported, which form highly fluorescent complexes with double-stranded DNA (dsDNA) with greater than 1000-fold fluorescence enhancement.
Abstract: The synthesis, proof of structure, and the absorption and fluorescence properties of two new unsymmetrical cyanine dyes, thiazole orange dimer (TOTO; 1,1'-(4,4,7,7-tetramethyl-4,7- diazaundecamethylene)-bis-4-[3-methyl-2,3-dihydro-(benzo-1,3-thiaz ole)-2- methylidene]-quinolinium tetraiodide) and oxazole yellow dimer (YOYO; an analogue of TOTO with a benzo-1,3-oxazole in place of the benzo-1,3-thiazole) are reported. TOTO and YOYO are virtually non-fluorescent in solution, but form highly fluorescent complexes with double-stranded DNA (dsDNA), up to a maximum dye to DNA bp ratio of 1:4, with greater than 1000-fold fluorescence enhancement. The dsDNA-TOTO (lambda max 513 nm; lambda maxF 532 nm) and dsDNA-YOYO (lambda max 489 nm; lambda maxF 509 nm) complexes are completely stable to electrophoresis on agarose and acrylamide gels. Mixtures of restriction fragments pre-labeled with ethidium dimer (EthD; lambda maxF 616 nm) and those pre-labeled with either TOTO or YOYO were separated by electrophoresis. Laser excitation at 488 nm and simultaneous confocal fluorescence detection at 620-750 nm (dsDNA-EthD emission) and 500-565 nm (dsDNA-TOTO or dsDNA-YOYO emission) allowed sensitive detection, quantitation, and accurate sizing of restriction fragments ranging from 600 to 24,000 bp. The limit of detection of dsDNA-TOTO and YOYO complexes with a laser-excited confocal fluorescence gel scanner for a band 5-mm wide on a 1-mm thick agarose gel was 4 picograms, about 500-fold lower than attainable by conventional staining with ethidium bromide.
680 citations
TL;DR: The result indicates that, contrary to previous proposals, pyrroloquinoline quinone is not the active site cofactor in mammalian copper amine oxidases, and suggests that this compound has a functional role at an enzyme active site.
Abstract: An active site, cofactor-containing peptide has been obtained in high yield from bovine serum amine oxidase. Sequencing of this pentapeptide indicates: Leu-Asn-X-Asp-Tyr. Analysis of the peptide by mass spectrometry, ultraviolet-visible spectroscopy, and proton nuclear magnetic resonance leads to the identification of X as 6-hydroxydopa. This result indicates that, contrary to previous proposals, pyrroloquinoline quinone is not the active site cofactor in mammalian copper amine oxidases. Although 6-hydroxydopa has been implicated in neurotoxicity, the data presented suggest that this compound has a functional role at an enzyme active site.
607 citations
TL;DR: A strong correlation is found between phosphorylation-driven activation of the signaling protein NtrC and microsecond time-scale backbone dynamics and a dynamic population shift between two preexisting conformations as the underlying mechanism of activation.
Abstract: Protein actions are usually discussed in terms of static structures, but function requires motion. We find a strong correlation between phosphorylation-driven activation of the signaling protein NtrC and microsecond time-scale backbone dynamics. Using nuclear magnetic resonance relaxation, we characterized the motions of NtrC in three functional states: unphosphorylated (inactive), phosphorylated (active), and a partially active mutant. These dynamics are indicative of exchange between inactive and active conformations. Both states are populated in unphosphorylated NtrC, and phosphorylation shifts the equilibrium toward the active species. These results support a dynamic population shift between two preexisting conformations as the underlying mechanism of activation.
603 citations
TL;DR: It is shown that the intracellular juxtamembrane segment of the receptor, known to potentiate kinase activity, is able to dimerize the kinase domains.
561 citations
TL;DR: A general method of assigning the non-exchangeable protons in the nuclear magnetic resonance spectra of small DNA molecules has been developed based upon two-dimensional autocorrelated (COSY) and nuclear Overhauser (NOESY) spectra in 2H2O solutions.
484 citations
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TL;DR: Understanding of the complex signaling networks downstream from RTKs and how alterations in these networks are translated into cellular responses provides an important context for therapeutically countering the effects of pathogenic RTK mutations in cancer and other diseases.
7,056 citations
TL;DR: This paper presents a meta-analysis of the chiral stationary phase transition of Na6(CO3)(SO4)2, a major component of the response of the immune system to Na2CO3.
Abstract: Ju Mei,†,‡,∥ Nelson L. C. Leung,†,‡,∥ Ryan T. K. Kwok,†,‡ Jacky W. Y. Lam,†,‡ and Ben Zhong Tang*,†,‡,§ †HKUST-Shenzhen Research Institute, Hi-Tech Park, Nanshan, Shenzhen 518057, China ‡Department of Chemistry, HKUST Jockey Club Institute for Advanced Study, Institute of Molecular Functional Materials, Division of Biomedical Engineering, State Key Laboratory of Molecular Neuroscience, Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China Guangdong Innovative Research Team, SCUT-HKUST Joint Research Laboratory, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China
5,658 citations
TL;DR: Detailed analyses of a relatively small number of representative proteins provide a foundation for understanding this large family of signaling proteins, which consists of two conserved components, a histidine protein kinase and a response regulator protein.
Abstract: ▪ Abstract Most prokaryotic signal-transduction systems and a few eukaryotic pathways use phosphotransfer schemes involving two conserved components, a histidine protein kinase and a response regul...
3,406 citations
Patent•
29 Jun 2001
TL;DR: In this article, a structural signal called for the display of the protein on the outer surface of a chosen bacterial cell, bacterial spore or phage (genetic package) is introduced into a genetic package.
Abstract: In order to obtain a novel binding protein against a chosen target, DNA molecules, each encoding a protein comprising one of a family of similar potential binding domains and a structural signal calling for the display of the protein on the outer surface of a chosen bacterial cell, bacterial spore or phage (genetic package) are introduced into a genetic package. The protein is expressed and the potential binding domain is displayed on the outer surface of the package. The cells or viruses bearing the binding domains which recognize the target molecule are isolated and amplified. The successful binding domains are then characterized. One or more of these successful binding domains is used as a model for the design of a new family of potential binding domains, and the process is repeated until a novel binding domain having a desired affinity for the target molecule is obtained. In one embodiment, the first family of potential binding domains is related to bovine pancreatic trypsin inhibitor, the genetic package is M13 phage, and the protein includes the outer surface transport signal of the M13 gene III protein.
3,093 citations
TL;DR: Many proteins that lack intrinsic globular structure under physiological conditions have now been recognized, and it appears likely that their rapid turnover, aided by their unstructured nature in the unbound state, provides a level of control that allows rapid and accurate responses of the cell to changing environmental conditions.
2,804 citations