Kittler L, Löber G
Institut für Molekulare Biotechnologie e.V., Jena, Germany.
J Photochem Photobiol B. 1995 Feb;27(2):161-6. doi: 10.1016/1011-1344(94)07071-u.
Supercoiled pUC19 DNA, photoreacted with psoralen derivatives (xanthotoxin (8-methoxypsoralen, 8-MOP), 4,5',8-trimethylpsoralen (TMP) and angelicin), influences the enzymatic activity of restriction enzymes in a different manner, although all the enzymes employed contain, within their recognition sites, suitable nucleic acid bases for photoproduct formation. The activity of the enzymes is strongly influenced by the photomodification of thymine residues within their recognition sites. 5'-TpA sequences favour intercalation as an essential prerequisite of the photoreaction, while 5'ApT sequences do not. This, in turn, influences photoproduct formation and the inhibition of the action of the restriction enzymes KpnI, SspI, DraI and RsaI, but not EcoRI and BamHI. The inhibitory effect is independent of the number of cleavage sites and also of whether monoaddition products or crosslinks are formed. Psoralen intercalation alone does not affect the activity of the restriction enzymes used.
超螺旋pUC19 DNA与补骨脂素衍生物（花椒毒素（8-甲氧基补骨脂素，8-MOP）、4,5',8-三甲基补骨脂素（TMP）和白芷素）进行光反应后，对限制酶的酶活性有不同影响，尽管所有使用的酶在其识别位点内都含有适合形成光产物的核酸碱基。酶的活性受到其识别位点内胸腺嘧啶残基光修饰的强烈影响。5'-TpA序列有利于嵌入，这是光反应的一个基本前提，而5'ApT序列则不然。这反过来又影响光产物的形成以及对限制酶KpnI、SspI、DraI和RsaI作用的抑制，但对EcoRI和BamHI没有影响。抑制作用与切割位点的数量无关，也与形成的是单加成产物还是交联产物无关。仅补骨脂素嵌入不会影响所使用的限制酶的活性。
