Fedorova O S, Adeenah-Zadah A, Knorre D G
Institute of Bioorganic Chemistry, Siberian Division of Russian Academy of Sciences, Novosibirsk.
FEBS Lett. 1995 Aug 7;369(2-3):287-9. doi: 10.1016/0014-5793(95)00733-p.
The intraduplex reaction of the alkylating reagent CIRCH2NHpd(TTCCCA) (X, ClR is p-(N-2-chloroethyl-N-methylaminophenyl) residue) with the target 26-mer d(TTGCCTTGAATGGGAAGAGGGTCATT) (P) in the presence of effectors was studied. The effectors used were Phn-L-pd(TTCAAGGC)p-L-Phn (E1) and Phn-L-pd(TGACCCTC)p-L-Phy (E2), where Phn is N-(2-hydroxyethyl)-phenazinium residue and L is NHCH2CH2NH spacer. The dependence of the alkylation extent of the target on the reagent concentration was treated using the equation derived earlier for the two-component system (reagent + target) to calculate association constants of X with P, PE1, PE2 and PE1E2. The latter were found to be Kxe1 = 6.75 x 10(5) M-1, Kxe2 = 4.15 x 10(4) M-1 and Kxe12 = 5.87 x 10(6) M-1 as compared with the affinity of X to P Kx = 2.16 x 10(4) M-1 in the absence of effectors. Taking into account the internal structure of the target, co-operativity parameters describing interactions in the tandem E1 x X x E2 arranged at the target were calculated as alpha 1 = 16, alpha 2 = 10 and alpha 12 = 139 for the duplexes PXE1, PXE2 and PXE1E2.
研究了烷基化试剂CIRCH2NHpd(TTCCCA)（X，ClR为对-(N-2-氯乙基-N-甲基氨基苯基)残基）与靶标26聚体d(TTGCCTTGAATGGGAAGAGGGTCATT)（P）在效应物存在下的双链内反应。所用的效应物为Phn-L-pd(TTCAAGGC)p-L-Phn（E1）和Phn-L-pd(TGACCCTC)p-L-Phy（E2），其中Phn为N-(2-羟乙基)-吩嗪鎓残基，L为NHCH2CH2NH间隔基。使用先前为双组分体系（试剂+靶标）推导的方程处理靶标的烷基化程度对试剂浓度的依赖性，以计算X与P、PE1、PE2和PE1E2的缔合常数。结果发现，与在无效应物时X对P的亲和力Kx = 2.16 x 10(4) M-1相比，后者分别为Kxe1 = 6.75 x 10(5) M-1、Kxe2 = 4.15 x 10(4) M-1和Kxe12 = 5.87 x 10(6) M-1。考虑到靶标的内部结构，计算了描述排列在靶标上的串联E1 x X x E2中相互作用的协同参数，对于双链体PXE1、PXE2和PXE1E2，分别为α1 = 16、α2 = 10和α12 = 139。
