Effect of poly(ethylene glycol) (PEG) spacers on the conformational properties of small peptides: a molecular dynamics study.
Poly(ethylene glycol) (PEG) is used as an inert spacer in a wide range of biotechnological applications such as to display peptides and proteins on surfaces for diagnostic purposes. In such applications it is critical that the peptide is accessible to solvent and that the PEG does not affect the conformational properties of the peptide to which it is attached. Using molecular dynamics (MD) simulation techniques, we have investigated the influence of a commonly used PEG spacer on the conformation properties of a series of five peptides with differing physical-chemical properties (YGSLPQ, VFVVFV, GSGGSG, EEGEEG, and KKGKKG). The conformational properties of the peptides were compared (a) free in solution, (b) attached to a PEG-11 spacer in solution, and (c) constrained to a two-dimensional lattice via a (PEG-11)(3) spacer, mimicking a peptide displayed on a surface as used in microarray techniques. The simulations suggest that the PEG spacer has little effect on the conformational properties of small neutral peptides but has a significant effect on the conformational properties of small highly charged peptides. When constrained to a two-dimensional surface at peptide densities similar to those used experimentally, it was found that the peptides, in particular the polar and nonpolar peptides, aggregated strongly. The peptides also partitioned into the PEG layer. Potentially, this means that at high packing densities only a small fraction of the peptide attached to the surface would in fact be accessible to a potential interaction partner.
School of Chemistry and Molecular Biosciences, and the Institute for Molecular Biosciences, University of Queensland, Brisbane QLD 4072, Australia.
Ying
Y
Xue
Megan L
ML
O'Mara
Peter P T
PP
Surawski
Matt
M
Trau
Alan E
AE
Mark
D000595:Amino Acid Sequence; D056004:Molecular Dynamics Simulation; D009842:Oligopeptides / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D011487:Protein Conformation; D012996:Solutions; D013499:Surface Properties
D009842:Oligopeptides; D012996:Solutions; D011092:Polyethylene Glycols