Tonic block of hCav3.1-hCav3.3chimeras by 1 μM application of ProTx I. Chimera nomenclature is as follows: hCav3.1 sequence in domains I-IV is denoted by “G”, hCav3.3 sequence is denoted by “I”. Note that block of hCav3.1 and Chimeras that contain Domain IV of hCav3.1 are similar (see top dashed line). The bottom slashed line represents percent tonic block of 1 μM ProTx I of wild type hCav3.3. [n = 5-6 per channel, at 1 μM]. Error bars reflect standard errors, asterisks denote statistical significance relative to hCav3.1 [*p < 0.05, **p < 0.01]. Currents were elicited by stepping from a holding potential of −110 mV to a test potential of −20 mV.