Photoaffinity cross-linking

QUANTUM YIELD PHOTOCHROMISM PHOTO-CROSS-LINKING PHOTOAFFINITY LABELING PHOTODIMERIZATION PHOTOISOMERIZATION PHOTOLYSIS FLASH PHOTOLYSIS... 

Figure 2 Double-stranded oligonucleotide photoprobes that simulate modified DNA and intended to cross-link to DNA-binding proteins. (A) Probe modeling interstrand cross-linking by cisplatin Source From Ref. [63], with permission from the American Chemical Society via the Rightslink service (license number 2458870278307 granted June 30, 2010). The benzophenone probe prior to reaction with DNA is shown in the lower part of the panel. (B) Photoaffinity probe for bacterial DNA repair proteins. TT is a simulated thymine dimer intended to be recognized as a site of damage in DNA, and T (two instances) is the diazirine thymine derivative T Source From Ref. [64], with permission from Wiley.

In summary, the inherent chemical susceptibility of the arenediazonium-based photoaffinity ligands does not make them a popular tool for routine photo-cross-linking studies. Examples of arenediazonium-based photophores that have been incoporated into peptides are given in Table 3. 

Chong, P. C., and Hodges, R. S. (1982). Photochemical cross-linking between rabbit skeletal troponin and alpha-tropomyosin. Attachment of the photoaffinity probe N-(4-azidobenzoyl-[2-3H]glycyl)-S-(2-thiopyridyl)-cysteine to cysteine 190 of alpha-tropomyosin. / Biol. Chem. 257, 9152-9160. 

Dziarski, R. 1991. Demonstration of peptidoglycan-binding sites on lymphocytes and macrophages by photoaffinity cross-linking. J Biol Chem 266 4713—4718. 

The studies of the testis LH receptor indicated that it had a molecular weight of 194000 and that it exists as a dimer with both subunits having a molecular weight of 100000 [10-13]. In contrast, photoaffinity labelling [14,15] and chemical cross-linking [16] of LH with ovarian membranes suggests that the rat ovarian receptor consists of three or four subunits. It is possible that in addition to tissue differences there are species differences in the numbers and size of the subunits, because different results have been obtained from bovine [17] and porcine ovaries [18]. 

Azidophenacyl)thioJuridine 5 -triphosphate (134) has been prepared by alkylation of 5-thlouridine 5 -triphosphate with 4-azidophenacyl bromide. This analogue is a substrate for E.coli RNA polymerase and once incorporated into RNA can be used to study RNA-protein or RNA-nucleic acids interactions by photo-activated cross-linking. Unlike other photoaffinity labels the cross-linking... 

---