Protein spikes

Fig. 2.18 Raw data from a model GPC spin column/microbore HPLC ESI-MS primary screen of 400 compounds with PKA protein spiked with both staurosporine and olomoucine, known ligands of PKA. (Left) TIC, UV trace at 214 nm, and corresponding mass chromatograms for olomoucine and...

Test well Bottom chamber serum protein spiked with test compound Top chamber PBS buffer only... 

The coronaviruses are typically associated with the common cold, and are so-called because of their crown-like halo of protein spikes. Since they are RNA-( + )-viruses, they are able to code for their own m-RNA, which codes for the proteins involved in replication and can thus reproduce without much help from the host cell. On this occasion, the human race has been lucky and until the animal vector for this virus is identified, there will be the ever-present fear that the next time it jumps species, it may have an improved ability to both infect and subsequently kill its victims. 

A EXPERIMENTAL FIGURE 4-38 Viral protein spikes protrude from the surface of an influenza virus virion. 

Viruses are very small particles composed of nucleic acid and protein. The entire virus particle is called the virion. At the center of the virion is the nucleic acid. Surrounding this is the capsid, which is a protein coat. The combination of the nucleic acid and the capsid is called the nucleocapsid, and, for some viruses, such as the rhinovirus, that is the extent of the particle. Many other viruses, including HIV, have a membrane envelope surrounding the nucleocapsid. Many viruses also have protein spikes that help it attach to its host cell. Figure 14.1 shows the main features of a virus. 

FIGURE 14.1 The architecture of a typical virus particle. The nucleic acid is in the middle, surrounded by a protein coat called the capsid. Many viruses also have an envelope membrane that is usually covered with protein spikes. 

One good choice would be a drug that attacks one of the specific protein spikes on the virus. This may be an antibody that attacks it, or a drug that blocks its ability to attach to the host cell. Another choice would be a drug that inhibits a key viral enzyme, such as the reverse transcriptase of a retrovirus, or the enzymes involved in repackaging the viruses. 

The use of species-specific spiking greatly enhances the traceability of the analytical procedure and improves the reliability of the results. On the other hand, the use of isotopically enriched metalloproteins provides a means to evaluate the analytical conditions, under which the metal center is most stable. Despite all the advantages of species-specific spiking for ICP-MS, it has to be mentioned that huge effort is necessary to produce and characterize an isotopically enriched protein spike. Therefore, this approach might be sensible in practice for the assay of only a few proteins or biomarkers. ... 

Figure 9 Three-dimensional cationic CITP of (A) blank (B) lysozyme (LYSO), creatinine (CREAT), conalbumin (CAL), y-amino-n-butyric acid (GABA), and ovalbumin (OVA) (C) OVA spiked with CREAT and GABA. Capillary 90 cm (length to the detector, 70 cm) x 75 p i.d. leader 10 mM potassium acetate and acetic acid with 0.3% HPMC, pH 4.75 terminator 10 mM acetic acid sample 10 to 30 mg/ml proteins dissolved in leader without HPMC voltage 20 kV. (From Gebauer, P. and Thormann, W.,. Chromatogr., 558, 423, 1991. With permission.)...

Results from experiments using the protocol above27 have shown that anti-Salmonella immunomagnetic beads could be used to unambiguously determine the presence of Salmonella choleraesuis from suspensions of bacterial mixtures. This target organism was also positively identified from spiked samples of river water, human urine, chicken blood, and 1 % milk. For the river water and urine samples, no cross-reactivity was observed and only protein... 

A technical challenge with this step is to achieve RNA extraction of uniform quality and efficiency for each fraction. This is because the amount of RNA in each sucrose gradient fraction varies considerably and the high concentration of sucrose in the bottom fractions interferes with phase separation in typical phenol-based extraction steps. To address these problems, we spike each fraction with an aliquot of a foreign (control) RNA, which can be used later to correct for differences in RNA recovery (and reverse transcription efficiency) between samples. We then remove sucrose from the samples by precipitation of total nucleic acid and protein with ethanol. To purify RNA, a standard Trizol (Invitrogen) extraction is performed as outlined later (also see product insert). 

Chimeric TMV particles containing the 5B19 epitope from the spike protein of murine hepatitis virus (MHV) fused near the C-terminus of TMV coat protein subunits were used to immunize mice intranasally (three doses per week for ten weeks) [46]. High IgG titers and moderate IgA titers specific to the peptide could be de-... 

Porcine epidemic diarrhea virus (PEDV) spike protein Tobacco leaf Systemic and mucosal immune response in mice immunized orally. 107... 

Relative extraction efficiencies of polar polymeric neutral, cation, and anion exchange sorbents (HLB, MCX, and MAX) for 11 beta antagonists and 6 beta agonists in human whole blood were probed.109 Initial characterization of MCX and MAX for acidic and basic load conditions, respectively, showed that both the agonists and antagonists were well retained on MCX, while they were recovered from MAX in the wash with either methanol or 2% ammonia in methanol (see Table 1.6). Blood samples were treated with ethanol containing 10% zinc sulfate to precipitate proteins and the supernatants loaded in 2% aqueous ammonium hydroxide onto the sorbents. After a 30% methanol and 2% aqueous ammonia wash, the analytes were eluted with methanol (HLB), 2% ammonia in methanol (MCX), or 2% formic acid in methanol (MAX). The best recoveries were observed with MCX under aqueous conditions or blood supernatant (after protein precipitation) spiked sample load conditions (see Table 1.7). Ion suppression studies by post-column infusion showed no suppression for propranolol and terbutaline with MCX, while HLB and MAX exhibited suppression (see Figure 1.6). 

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