Spectrin Motifs are Detected in Plant and Yeast Genomes.

Using several consensus sequences for 106 amino acid residue α-spectrin repeat segment as well as ours developed by using a genetic semihomology algorithm as probes we searched plant and S. cerevisiae databases by using BLAST programme in order to find proteins similar to spectrin. Among many sequences showing rather high level of homology in very short (few amino acid residues) segments we found nine higher plants and yeast sequences displaying low homology in longer segments. The homology of these sequences to α-spectrin was further analysed by using a SEMIHOM programme based on the genetic semihomology algorithm. Moreover, homology to SH3 domain was also tested by using constructed SH3 domain consensus sequence. In addition, the analysis of the sequence of A16 clone which was obtained by PCR amplification of S. tuberosum DNA fragment by using α-spectrin primers, cloning and sequencing. More detailed analysis revealed the existence of homologous sequences that are characterised by the presence of at least one homologous ~100 amino acid residue, some of them containing conservative tryptophan residues at position 12 and/or 45 and also another segment homologous to SH3 domain.