Potassium channel is specific for transport of potassium ion. The conserved K binding site of potassium channel contains unique amino acid sequence: Thr-Val-Gly-Tyr-Gly. One potassium channel has specific sites to bind maximal four K ions. Close to open of K channel is regulated by and K can rapidly shift from one binding site to another one farther up the channel because of. a. rotation of one negatively charged subunit of K channel; charge repulsion b. rotation of one positively charged subunit of K channel; charge repulsion c. rotation of one negatively charged subunit of K channel: polar-polar interactions d. rotation of one positively charged subunit of K channel; polar - polar interactions