INDUCTION OF POLYNUCLEOTIDE-PROTEIN CROSS-LINKAGES BY ULTRAVIOLET-IRRADIATION - PECULIARITIES OF THE HIGH-INTENSITY LASER-PULSE IRRADIATION
INDUCTION OF POLYNUCLEOTIDE-PROTEIN CROSS-LINKAGES BY ULTRAVIOLET-IRRADIATION - PECULIARITIES OF THE HIGH-INTENSITY LASER-PULSE IRRADIATION
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DOI：
10.1111/j.1432-1033.1986.tb09837.x
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发表时间：
1986-08-15
期刊：
影响因子：
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通讯作者：
RUBIN, LB
中科院分区：
文献类型：
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作者：
BUDOWSKY, EI;AXENTYEVA, MS;RUBIN, LB
低强度(1015光子cm-2 S-1,254 nm)和高强度[(1.6-6.8)倍]诱导大肠杆菌核糖体30S亚基核糖核糖核酸-蛋白质交联的效率和特异性。1024个光子厘米-2 S-1。2 6 6 nm，脉冲宽度10-8 S]紫外光辐射。在前一种条件下，蛋白质S4、S7和S9/S11，在后一种条件下，这些蛋白质与S3、S18和S20一起与16S RNA交联。双光子过程在后一种情况下工作。在2-巯基乙醇存在下，通过较高的激发态直接或通过寿命小于25 ns的活化中间体发生交联。这样形成的交联键是特定的，即它们在激发之前在天然(未受干扰的)络合物中接触的大分子区域之间形成。与单步激发相比，两步激发的交联率(每吸收一个光子)提高了20-100倍，并且在一个脉冲中产生了可分析的交联数。只有16S RNA的U-1239碱基通过低强度辐射与蛋白质S7发生交联，而邻近的G-1240碱基也参与了激光诱导的交联。从前一种情况过渡到后一种情况，可以将辐射持续时间从几分钟减少到几纳秒。
The efficiency and specificity of RNA-protein cross-linking in the 30S subunit of Escherichia coli ribosomes, induced by low-intensity (1015 photons cm-2 s-1, 254 nm) and high-intensity [(1.6-6.8) .times. 1024 photons cm-2 s-1. 266 nm, pulse duration 10-8 s] ultraviolet radiation, are studied. Under the former conditions proteins S4, S7 and S9/S11, and under the latter conditions these proteins together with S3, S18 and S20, are cross-linked to 16S RNA. Biphotonic processes operate in the latter case. In the presence of 2-mercaptoethanol cross-linking occurs either directly, via a higher excited state or via activated intermediates with life-times less than 25 ns. Cross-links thus formed are specific, i.e., they are formed between regions of macromolecules which are in contact in the native (non-disturbed) complex prior to excitation. The efficiency of cross-linking (per photon absorbed) is 20-100 times higher upon two-step excitation as compared with single-step excitation and an analysable number of cross-links are produced in a single pulse. Only base U-1239 of 16S RNA is cross-linked to protein S7 by low-intensity radiation, whereas the adjacent base, G-1240 is also involved in laser-induced cross-linking. A transition from the former to the latter conditions allows one to reduce the duration of irradiation from several minutes to several nanoseconds.