Figure 3

Multiple sequence alignment for the transmembrane domain (TMD) regions of the putative diatom GPCRs. Highlighted regions represent the most conserved residue positions among the diatom sequences. Asterisks denote residue positions conserved across all sequences and circles denote residue positions critical in family C GPCR activation or conserved across metazoan class C receptors. H_sapie_GABAB, Homo sapiens GABBR2 protein (GI: 34191359); X_tropi_GABAB, Xenopus tropicalis GABAB receptor 2 (GI: 186972153); D_pulex_GABAB, Daphnia pulex GABAB receptor (GI: 321470990).