Figure 2.

Correlation between transmembrane helices and exon-intron structure in plant and human chromaffin cytochrome b561 proteins and genes. For each protein-gene pair, the protein is shown in the top line with the transmembrane helices as gray bars, and the gene organization is shown below with exons as grey and introns as white bars. The first exon encodes one (Artb561-2), two (Artb561-1 and Hosb561-1) or three (Artb561-4 and Orsb561) transmembrane helices. Numbers represent nucleotide positions. Transmembrane regions were predicted with TMHMM [43].