Question: 7. (6 points) Pardaxins are toxic peptides used by certain species of fish for a defense mechanis…


7. (6 points) Pardaxins are toxic peptides used by certain species of fish for a defense mechanism Pardaxins are membrane active peptides that can work as highly effective antibiotics. At high concentrations, pardaxins can even lyse red blood cells. The primary sequence for one of the pardaxins, Pa4, is given below. G-F-F-A-L-I-P-K-1-1-S-S-P-L-F-K-T-L-L-S-A-V-G-S-A-L-S-S-S-G-E-Q-E a) For each amino acid is the pardaxin sequence above, identify whether it is hydrophobic (underline in yellow), hydrophilic (underline in blue), or charge alone indicates that this peptide is more likely to be found in membranes rather than aque d (underline in red). Explain why the primary sequence ous solution. b) Experimentally determined structures of pardaxin indicate that amino acids 2-10 and 13-27 form alpha helices. Plot residues 13-27 on the helical wheel (using positions 1-15) and color each amino acid as in part (a). 15 13 3 10

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7. (6 points) Pardaxins are toxic peptides used by certain species of fish for a defense mechanism Pardaxins are membrane active peptides that can work as highly effective antibiotics. At high concentrations, pardaxins can even lyse red blood cells. The primary sequence for one of the pardaxins, Pa4, is given below. G-F-F-A-L-I-P-K-1-1-S-S-P-L-F-K-T-L-L-S-A-V-G-S-A-L-S-S-S-G-E-Q-E a) For each amino acid is the pardaxin sequence above, identify whether it is hydrophobic (underline in yellow), hydrophilic (underline in blue), or charge alone indicates that this peptide is more likely to be found in membranes rather than aque d (underline in red). Explain why the primary sequence ous solution. b) Experimentally determined structures of pardaxin indicate that amino acids 2-10 and 13-27 form alpha helices. Plot residues 13-27 on the helical wheel (using positions 1-15) and color each amino acid as in part (a). 15 13 3 10

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