Biophysical monitors

Keywords Biophysical monitors Chemical synthesis of proteins Copper binding Expressed protein ligation Interaction of PrP with small molecules... 

The last example shows that chemical synthesis of proteins can be a useful tool to study pertinent questions in biochemistry. Its main advantage so far relates to its capability to introduce unnatural amino acids, specific isotope labels, biophysical monitors, or very important posttranslational modifications. The latter modification the introduction of a GPI anchor or a GPI anchor mimic onto PrP, has been the subject of further research. These experiments were not solely directed towards specific questions of PrP research but also towards development of a general method to modify proteins with a GPI anchor. 

In addition, there is the Biophysical Monitoring Program for Climatic Change operated by the National Oceanographic and Aerometric Administration of the U.S. Department of Commerce. This data base collects data on carbon dioxide, ozone, aerosols, precipitation, solar radiation, and fluorocarbon levels at stations located worldwide. This is an attempt to measure long-term trends in factors affecting climatic change. 

In health and biophysical monitoring, they can be used for cardiovascular monitoring, monitoring the vital signs of infants, monitoring clinical trials, health and fitness, home healthcare, hospitals, medical centers, assisted-living units, etc. 

Demchenko AP, Mely Y, Duportail G, Klymchenko AS (2009) Monitoring biophysical properties of lipid membranes by environment-sensitive fluorescent probes. Biophys J 96 3461-3470... 

Vibrational microspectroscopy provides a unique means for molecular level structure characterization of a variety of biological processes associated with skin. For the past several years, this laboratory has utilized Raman and IR spectroscopy, microscopy, and imaging to monitor the biophysics of the skin barrier, mechanisms of drug permeation and metabolism in intact tissue, and, more recently, the complex events that transpire during wound healing in an ex vivo skin model [1-6]. 

Fig. 25 (a) DNA release from EDOPC-DNA lipoplexes after addition of negatively charged lipid dispersion, as monitored by FRET (CM, oleic acid DOPA, dioleoyl phosphatidic acid DOPG, dioleoyl phosphatidylglycerol CL, cardiolipin DOPS, dioleoyl phosphatidylserine PI, phospha-tidylinositol). (b) Fraction of released DNA from EDOPC lipoplexes 10 min after addition of the respective anionic liposomes (c) X-ray diffraction patterns of mixtures of EDOPC and anionic liposome dispersions the respective structures are shown schematically on the left side (reproduced with permission from [98] copyright (2004) Biophysical Society)... 

Figure 19 Time-dependent fluorescent monitoring of free Mg + in neuroblastomas cells demonstrates the Li+/Mg + competition that releases bormd Mg + (curve B) Li-perfused cells, compared to rmtreated cells (curve A). Each frame represents 0.33 seconds. (Ref. 124. Reproduced by permission of Biophysical Society)...

These brief comments are intended to emphasize the critical need to use carefully purified and monitored nonaqueous solvents in any biophysical studies. Investigators, particularly physical chemists, oriented to studies in aqueous solution may tend to overlook the chemical properties of nonaqueous solvents. 

The substantial contributions of calorimetry and infrared spectroscopy to our knowledge base of SC biophysics speaks for themselves. Most notably, the pivotal role of the intercellular lipid domains in SC barrier function has been elucidated and has elevated the understanding of this complex membrane to a new level. In turn, this has allowed mechanisms of permeation and mechanisms of penetration enhancement to be examined and identified. Furthermore, the opportunity to monitor the uptake and distribution of topically administered chemicals into and within the SC offers a level of detail and quantification of the permeation process, in vivo in humans, that was unimaginable a decade ago. The variety of potential applications of these findings is considerable and will form the basis of substantial further work. 

The insertion of biophysical probes into protein sequences gives an opportunity to monitor various biochemical processes, such as protein-protein interaction. In order to develop potential biosensors, disruption of the protein cooperations can be coupled to some form of signaling event, such as a fluorescence change. Ayers et al. (28) reported on the interaction between the Src homology... 

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