Base modification

Modified residues can be detected by reverse transcriptase methods or end-labelled methods after an acidic aniline cleavage (Section 4.4.3). Hydrazine modifications can only be performed under denaturing conditions. 

2) or A (N7) under native conditions (Section 4.4.2.3). Modified residues can be detected directly by reverse transcriptase methods or after acidic aniline cleavage of end-labelled species. 

denaturing conditions, or Section 4.4.2.2, native conditions). Modification at A (Nl) and C (N3) can be identified by reverse transcriptase methods while identification of G (N7) modifications by reverse transcriptase methods or end-labelled methods (Section 4.4.3) requires a borohydride-reduction followed by an acidic aniline cleavage (Section 4.4.2.2). Kethoxal Probing G (Nl and N2). (Section 4.4.2.4, native conditions, or follow Section 4.4.2.4, denaturing conditions), but incubate for 2 min at 95°C. Modified residues can be detected directly by the reverse transcriptase method. 

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Strand Breakage DNA Base Modification Deoxyribose Fragmentation... 

Olinski, R., Zastawny, T., Budzbon, J., Skokowski, J., Zegarski, W. and Dizdaroglu, M. (1992). DNA base modifications in chromatin of human cancerous tissues. FEBS Lett. 309, 193-198. 

Frenkel, K. and Chrzan, K. (1987). Hydrogen peroxide formation and DNA base modification by tumor promoter-activated polymorphonuclear leukocytes. Carcinogenesis 8, 455-460. 

HPLC-MS/MS Measurement of One- and Two-Photon Induced DNA Base Modifications... 

Sequencing of parasite genes provides a powerful tool for the accurate identification of parasites and for systematic studies (Johnson and Baver-stock, 1989 Reddy, 1995 McManus and Bowles, 1996), and is based on either of the two original protocols (Sanger et al., 1977 Maxam and Gilbert, 1980). Cycle-sequencing (Murray, 1989), a PCR-based modification of the... 

Figure 1.43 indicates major sites of reactivity within the ring structures for nucleophilic displacement reactions. Cytosine, thymine, and uracil all react toward nucleophilic attack at the same two sites, the C-4 and C-6 positions. The presence of powerful nucleophiles, even at neutral pH, can lead to significant base modification or cleavage with pyrimidine residues (Debye, 1947). For instance, hydrazine spontaneously adds to the 5,6-double bond, initiating further ring reactions,... 

Figures 18.24 through 18.26 illustrate these PEG-based modification reagents. The methods for their use follow the same general protocol guidelines as discussed in previous sections...

The possible prooxidant effects of a major lipophilic antioxidant vitamin E (a-tocopherol) have already been discussed in Chapter 25. Yamashita et al. [82] showed that a-tocopherol induced extensive DNA damage including base modification and strand breakage in the... 

Figure 3. Purine riboside (PR) hydration and the effect of base modification Y.

Aich P, Sen R, Dasgupta D (1992b) Role of magnesium ion in the interaction between chromomycin A3 and DNA binding of chromomycin A3 — Mg + complexes with DNA. Biochemistry 31 2988-2997 Akman SA, Doroshow JJH, Thomas G, Burke J, Dizdaroglus M (1992) DNA base modifications induced in isolated human chromatin by NADH de hydrogenase-catalyzed reduction of doxorubicin. Biochemistry, 31 3500-3506... 

Figure 4 Recognition elements of tRNA° ". Highlighted in blue with bars are the recognition elements for Gln-tRNA° " synthesis by GatCAB and GatDE. The U1-A72 base pair is a common identity element, while antideterminants for noncognate tRNAs are scanned for in the D-loop. Highlighted in magenta are the identity elements of tRNA° " for GlnRS.tRNA " from Bacillus subtilis is shown, but base modifications at positions 32-38 and 33-37 allow base pairing in E. coll tRNA " .

Tandem base modifications thymine hydroperoxides, 933 uracil hydroperoxides, 935, 936 Tantalum(V) complexes... 

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