The molecular basis of wobbling: an alternative hypothesis.

The molecular basis of Crick's wobble hypothesis rests upon the assumption that the wobble base (base closest to the 5'-end of the anticodon) is able to shift its position within the anticodon by +/- 2.5 A. Since there are no experimental clues that such shifts do indeed occur, an alternative hypothesis is proposed. It is based upon the observation that a tertiary bond within the tRNA, the C56/G19-bond, is a modified Watson-Crick-bond with the peculiarity of uneven distances between the points of Watson-Crick-contact. Furthermore it is pointed out that C56, as far as its relation to the ribose-phosphate-backbone is concerned, bears a definite resemblance to the wobble base. On these grounds, the C56/G19-bond is discussed as the possible model for all molecular wobble constellations, rendering invalid the need for any shifts within the ribose-phosphate backbone of the anticodonic loop.