J. Biol. Chem., Vol. 261, Issue 16, 7253-7256, 06, 1986
Different conformations of the 3' termini of initiator and elongator transfer ribonucleic acids. An EPR study
RH Pscheidt and BD Wells
The 3' ends of transfer ribonucleic acids were covalently labeled with a
nitroxide spin label. The 3' end of initiator tRNA (tRNAMetf) from
Escherichia coli shows different motional behavior than the 3' terminus of
elongator tRNAs as monitored by EPR. The line shapes of the EPR spectra are
quite sensitive to the buffer conditions, as shown by measurements in 4
different buffers. The data are consistent with a constrained or folded
back 3' terminus in the initiator tRNA as opposed to the freely rotating
elongator 3' terminus. The EPR spectra are also sensitive to aggregation of
the tRNA.