Protein screening methods

After screening for toxicity, identification and/or quantification assays may need to be carried out if the screening method is not specific for the cyanobacterial toxin(s) under investigation. Suitable assays for these purposes include the physicochemical assays, HPLC, MS, and CE, and to some extent the immunoassays and protein phosphatase inhibition assays summarized in Section 2. 

The screening method based on diameter of halos yielded only five strains with at least 20% more PG than wild t> e. Most attempts to enhance pectinase production have been made in filamentous fiingi, in which enzyme production is regulated by induction and catabolite repression mechanisms [8], By contrast, PG produced by marxianus is constitutive and not subject to catabolite repression [6], Failure to find greatly enhanced secretion levels is consistent with the idea of a constitutive gene that is capable of only modest further induction. PG was found in this study to be already the most prolific secreted protein of K. marxianus. 

Jebanathirajah, J. A. Andersen, S. Blagoev, B. Roepstorff, P. A rapid screening method to monitor expression of recombinant proteins from various prokaryotic and eukaryotic expression systems using matrix-assisted laser desorption ioniza-tion-time-of-flight mass spectrometry. Anal. Biochem. 2002, 305, 242-250. 

The ability to display proteins on the surface of an organism has been exploited as a screening method, typically in conjunction with fluorescence-activated cell sorting (FACS) [37,47,48]... 

Geddie, M.L., Rowe, L.A., Alexander, O.B. and Matsumura, I. (2004) High throughput microplate screens for directed protein evolution. Methods in Enzymology, 388, 134-145. 

The most widely used screening method for tuberculous infection is the tuberculin skin test, which uses purified protein derivative (PPD). Populations most likely to benefit from skin testing are listed in Table 49-2. 

Jancarik J, Kim SH. 1991. Sparse matrix sampling a screening method for crystallization of proteins. J Appl Cryst 24 409-411. 

Schneider, G., Neidhart, W., and Adam, G. Integrating virtual screening methods to the quest for novel membrane protein ligands. Curr. Med. Chem. CNS Agents 2001, 3, 99-112. 

An important question that needs to be addressed in any screening study is the determination of whether or not the ligand is non-covalently bound to the active site of the target protein. A number of simple GPC spin column ESI-MS screening methods have been developed to answer this question. These methods include the use of mutated proteins where the active site has been modified, GPC spin column/ESI-MS coupled with NMR (GPC spin column/MS/NMR) and displacement of known binders. Titration experiments with molar excesses of ligand to protein (described below in Section 2.3.3.2.4) can also be used to determine whether single or multiple binding sites are available in the protein. 

There has been substantial progress in the construction of phage-displayed peptide libraries and in screening methods with the libraries to isolate peptide receptor ligands [66,116-119]. Phage display peptide libraries offer opportunities to characterize peptide binding specificity of important proteins, such as... 

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