Design, synthesis and structural characterization of model heterodimeric coiled-coil proteins.
We report the design and synthesis of model heterodimeric coiled-coil proteins and the packing contribution of interchain hetero-hydrophobic side-chains to coiled-coil stability. The heterodimeric coiled-coils are obtained by oxidizing two 35-residue polypeptide chains, each containing a cysteine residue at position 2 and differing in amino acid sequences in the hydrophobic positions ("a" and "d") responsible for the formation and stabilization of the coiled-coil. In each peptide, a single Ala residue was substituted for Leu at position "a" or "d". The formation and stability of heterodimeric coiled-coils were investigated by circular dichroism studies in the presence and absence of guanidine hydrochloride and compared to the corresponding homodimeric coiled-coils. The coiled-coil proteins with an Ala substitution at position "a" were less stable than those with an Ala substitution at position "d" in both the homodimeric (Ala-Ala interchain interactions) and heterodimeric (Leu-Ala interchain interactions ) coiled-coils. The 70-residue disulfide bridged peptides (homo- and heterodimeric coiled-coils) can be readily separated by reversed-phase chromatography (RPC) even though they have identical amino acid compositions as well as in the hydrophobic "a" and "d" positions. The elution of the 70-residue peptides prior to their corresponding 35-residue monomers suggests that these proteins are retaining a large portion of their coiled-coil structure during RPC at pH2 and their retention behavior correlates with protein stability.
Zhu
B Y
BY
Department of Biochemistry, University of Alberta, Edmonton, Canada.
Zhou
N E
NE
Semchuk
P D
PD
Kay
C M
CM
Hodges
R S
RS
D000595:Amino Acid Sequence; D002851:Chromatography, High Pressure Liquid; D008956:Models, Chemical; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D017433:Protein Structure, Secondary; D011506:Proteins / Q000138:chemical synthesis / Q000737:chemistry*; D012995:Solubility; D014867:Water / Q000737:chemistry
D010455:Peptides; D011108:Polymers; D011506:Proteins; D014867:Water