Effects of N- and C-terminal addition of oligolysines or native loop residues on the biophysical properties of transmembrane domain peptides from a G-protein coupled receptor.
Transmembrane domains (TMDs) of G-protein coupled receptors (GPCRs) have very low water solubility and often aggregate during purification and biophysical investigations. To circumvent this problem many laboratories add oligolysines to the N- and C-termini of peptides that correspond to a TMD. To systematically evaluate the effect of the oligolysines on the biophysical properties of a TMD we synthesized 21 peptides corresponding to either the second (TPIFIINQVSLFLIILHSALYFKY) or sixth (SFHILLIMSSQSLLVPSIIFILAYSLK) TMD of Ste2p, a GPCR from Saccharomyces cerevisiae. Added to the termini of these peptides were either Lys(n) (n = 1,2,3) or the corresponding native loop residues. The biophysical properties of the peptides were investigated by circular dichroism (CD) spectroscopy in trifluoroethanol-water mixtures, sodium dodecyl sulfate (SDS) micelles and dimyristoylphosphocholine (DMPC)-dimyristoylphosphoglycerol (DMPG) vesicles, and by attenuated total reflection Fourier transform infrared (ATR-FTIR) in DMPC/DMPG multilayers. The results show that the conformation assumed depends on the number of lysine residues and the sequence of the TMD. Identical peptides with native or an equal number of lysine residues exhibited different biophysical properties and structural tendencies.
Cano-Sanchez
Patricia
P
Department of Chemistry, College of Staten Island and Macromolecular Assemblies Institute of the City University of New York, Staten Island, New York 10314, USA.
Severino
Beatrice
B
Sureshbabu
V V
VV
Russo
Joe
J
Inui
Tatsuya
T
Ding
Fa-Xiang
FX
Arshava
Boris
B
Becker
Jeff
J
Naider
Fred
F
D000595:Amino Acid Sequence; D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D004134:Dimyristoylphosphatidylcholine / Q000737:chemistry; D008823:Micelles; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000737:chemistry*; D011107:Polylysine / Q000737:chemistry*; D043562:Receptors, G-Protein-Coupled / Q000737:chemistry*; D018000:Receptors, Peptide / Q000737:chemistry*; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D012997:Solvents / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared
D008823:Micelles; D010446:Peptide Fragments; D043562:Receptors, G-Protein-Coupled; D018000:Receptors, Peptide; D012997:Solvents; D011107:Polylysine; D004134:Dimyristoylphosphatidylcholine