The identification of genes whose expression is regulated by recoding events is often serendipitous. In the framework of our studies on glycosidases from hyperthermophiles, we identified in the genome of the archaeon S.solfataricus a split gene encoding a putative a-fucosidase, which could be expressed through programmed À1 frameshifting (24) . We tackled this issue by studying the expression of fucA1 in S.solfataricus and in E.coli to overcome the problems connected to the scarcity of expression of the a-fucosidase gene and to the manipulation of hyperthermophiles. As already reported by others, in fact, it is a common strategy to study recoding events from different organisms in E.coli (23, 33) .