Engineering of the hydrophobic core of an alpha-helical coiled coil.
The amino acid sequence that forms the alpha-helical coiled coil structure has a representative heptad repeat denoted by defgabc, according to their positions. Although the a and d positions are usually occupied by hydrophobic residues, hydrophilic residues at these positions sometimes play important roles in natural proteins. We have manipulated a few amino acids at the a and d positions of a de novo designed trimeric coiled coil to confer new functions to the peptides. The IZ peptide, which has four heptad repeats and forms a parallel triple-stranded coiled coil, has Ile at all of the a and d positions. We show three examples: (1) the substitution of one Ile at either the a or d position with Glu caused the peptide to become pH sensitive; (2) the metal ion induced alpha-helical bundles were formed by substitutions with two His residues at the d and a positions for a medium metal ion, and with one Cys residue at the a position for a soft metal ion; and (3) the AAB-type heterotrimeric alpha-helical bundle formation was accomplished by a combination of Ala and Trp residues at the a positions of different peptide chains. Furthermore, we applied these procedures to prepare an ABC-type heterotrimeric alpha-helical bundle and a metal ion-induced heterotrimeric alpha-helical bundle.
Kiyokawa
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Department of Applied Biology, Kyoto Institute of Technology, Matugasaki, Sakyou-ku, Kyoto 606-8585, Japan.
Kanaori
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Tajima
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Tanaka
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D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D002412:Cations / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000737:chemistry; D005656:Fungal Proteins / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008958:Models, Molecular; D010455:Peptides / Q000138:chemical synthesis* / Q000737:chemistry; D015202:Protein Engineering; D011494:Protein Kinases / Q000737:chemistry; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D020449:Repetitive Sequences, Amino Acid; D029701:Saccharomyces cerevisiae Proteins; D013057:Spectrum Analysis; D013696:Temperature
D002412:Cations; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D010455:Peptides; D029701:Saccharomyces cerevisiae Proteins; D011494:Protein Kinases