Purification and initial characterization of Plasmodium falciparum K+ channels PfKch1 and PfKch2 produced in Saccharomyces cerevisiae

摘要

Modelling and membrane topology prediction of PfKch1fl and PfKch2fl. Homology modelling of residues 570 —1966 of PfKch1 (a) and residues 140—1461 of PfKch2 (c) using Phyre2 and the transmembrane topologies of full length PfKch1 (b) and full length PfKch2 (d) using a combination of Phyre2, TOPCONS and TMHMM (b, d) (see Additional file 1: Fig.S1). The Phyre2 modelled transmembrane helixes TM3 to TM8 are colored blue, red, yellow, purple, orange and tints, respectively. The positions of Arginine and Lysine residues potentially involved in voltage dependency are shown in cyan while the consensus pore region is depicted in gray. Numbers in the topology models indicate amino acids initiating or termination transmembrane helixes. Red spheres show the location of positively charged amino acids presumably involved in voltage dependent gating. Helices involved in possible voltage sensing are shown in blue while helices involved in K+ selectivity are depicted in orange. The pore signature sequence TXXTXGYG is shown in purple. The locations of predicted RCK1 and RCK 2 domains (regulator of conductance of K + channels) are shown in green and red, respectively, and numbered I, II, III, IV and V. White boxes indicate insertions that are not found in the SLO1 channels from e.g. man and zebrafish. An arrow indicates the position of the C-terminal end of the truncated PfKch11−1094 channel