Structure and expression of LeMA-1, a tomato protein belonging to the SEC18-PAS1-CDC48-TBP-1 protein family of putative Mg(2+)-dependent ATPases.

cDNA clones of a tomato protein, called Lycopersicum esculentum putative Mg(2+)-dependent ATPase (LeMA-1), were isolated from a cDNA library. Sequence comparison of the tomato protein with other genes in the database revealed that the protein is highly homologous to a human protein called TBP-1 and a yeast Tat-binding-analogue protein YTA1A. All three proteins belong to the recently discovered protein family of putative Mg(2+)-dependent ATPases and form within this family a subgroup of proteins involved in controlled protein degradation and possibly also in transcriptional regulation. Expression of the mRNA of LeMA-1 could be monitored in several plant tissues. LeMA-1 is the first member of this subgroup of proteins isolated from plants.