A specific spin labeling of the anticodon of E.coli tRNAGlu

Specific spin-labeling of transfer ribonucleic acid molecules

“…it is obvious that the exact.location of the spin label on each tRNA molecule has to be known.. As seep in the figure, both ASL-and BSL-tRNAfMet give the same elution profile in which there is no absorbance at 330 nm under peak 4, the relative intensity of which is strongly decreased as compared to same peak in the control pattern. On the other hand, a large increase in relative intensity is apparent in peak lb whose fractions, after desalting, yielded an EPR spectrum representative of a spin-labeled oligonucleotide (5). Analysis of this tRNA fragment by two-dimensional T.L.C.…”

“…The plate was eluted in the first dimension with isobutyric acid-0. Figure 1 and are typical of molecules carrying only one spin.label (1)(2)(3)(4)(5).…”

“…loss in relative intensity that is apparent in peak 11 and which is accompanied by an increase of about the same order of magnitude in relative intensity in peak 8. After desalting, the material obtained from peak 8 gave an EPR spectrum related to a spinlabeled oligonucleotide (5). Analysis of the material recovered from peak 11 of the control elution yielded the fragment Cm2UCAUAACCCG of the anticodon region of tRNAfMet (15).…”

“…We then conclude from this that the 3'end terminal adenosine was indeed transformed into its morpholino derivatives MSL. Table 1 summarizes the results and gives the location of labeling and the nature of the attachment of the labels as based on previous results (4)(5)(6)10,16). For all the elution patterns, only one peak contains the paramagnetic material, the analysis of which showing that in all cases only one position on the tRNA molecule carries the label, and this in spite of the fact that other groups are also succeptible to react.…”

“…Latter, the group of Nishimura (4) succeeded in spin-labeling the s 4U residue located in the region between hU stem and CCA stem of various E.coli tRNAs. In a previous communication (5) we reported the selective labeling of the rare base s2U* at the wobble position of the anticodon of E.coli tRNAGlu using a spin label anhydride (ASL).…”