FOOTPRINTING EVIDENCE FOR CLOSE CONTACTS OF THE YEAST TRANSFER-RNAASP ANTICODON REGION WITH ASPARTYL-TRANSFER RNA-SYNTHETASE

Chemical footprinting experiments on brewer's yeast tRNAAsp complexed to its cognate aspartyl-tRNA synthetase are reported: they demonstrate that bases of the anticodon loop, including the anticodon itself, are in close proximity with the synthetase. Contacts were determined using dimethylsulfate as the probe for testing reactivity of guanine and cytosine residues in free and complexed tRNA. Results correlate with the decrease in aspartylation activity of yeast tRNAAsp molecules mutated at these contact positions and will be compared with other structural data arising from solution and crystallographic studies on the aspartic acid complex. © 1992.