Figure 6. Parasite Ca_v channel homologues show similarity to human Ca_v channels in the pore region.

(A) Schematic showing the four-domain structure of human Ca_v channels, with the pore loop of each domain shown in red. Cylinders indicate TMDs, and plus signs indicate the charged voltage sensor regions. (B) Multiple sequence alignments of the pore domains of human Ca_v channels with parasite Ca_v channel homologues. Only those parasite homologues containing four putative domains are shown. Sequences of human Ca_v1.2 (L-type), Ca_v2.1 (P/Q-type), Ca_v2.2 (N-type) and Ca_v3.2 (T-type) channels, as well as the S. cerevisiae Cch1 Ca²⁺ channel (ScCch1), are shown. L. braz denotes L. braziliensis. Selected human Na_v isoforms are included, to allow comparison with the related Ca_v channels. The locations of acidic residues (underlined) forming an acidic ring motif in human Ca_v1.2 channels are indicated by asterisks. The overall motif formed by all four domains at this locus is indicated to the right of the Domain IV alignment for each channel homologue.