Amino Acids

, Volume 46, Issue 1, pp 177–186

Proline-glutamate chimera’s side chain conformation directs the type of β-hairpin structure

Authors

  • Jyotirmoy Maity
    • Institut für Chemie und BiochemieFreie Universität Berlin
  • Ulla I. M. Gerling
    • Institut für Chemie und BiochemieFreie Universität Berlin
  • Stella Vukelić
    • Institut für Chemie und BiochemieFreie Universität Berlin
  • Andreas Schäfer
    • Gerätezentrum BioSupraMolFreie Universität Berlin
    • Institut für Chemie und BiochemieFreie Universität Berlin
Original Article

DOI: 10.1007/s00726-013-1610-1

Cite this article as:
Maity, J., Gerling, U.I.M., Vukelić, S. et al. Amino Acids (2014) 46: 177. doi:10.1007/s00726-013-1610-1
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Abstract

Our aim was to study the impact of two proline chimeras, containing a glutamic acid side chain in cis- or trans-configuration, on secondary structure formation. We further investigated to what extent the configuration of the side chain contributes to the overall peptide conformation. We used a 10 residue peptide (IYSNPDGTWT) that forms a β-hairpin in water. The turn-forming proline was substituted with either a cis- or trans-proline-glutamic acid chimera, resulting in the peptides IYSNPcis-EDGTWT (P1_Pcis-E) and IYSNPtrans-EDGTWT (P1_Ptrans-E). We studied the conformation of the modified peptides by circular dichroism (CD) and NMR-spectroscopy, and SEC/static light scattering (SLS) analysis. NMR analysis reveals that the modified peptides maintain the β-hairpin conformation in aqueous solution. At 5 °C and pH 4.3, the peptide (P1_Pcis-E) was found to adopt two coexisting β-hairpin conformations (2:2 β-hairpin, and 3:5 β-hairpin). In contrast to that, the peptide (P1_Ptrans-E) adopts a 2:2 β-hairpin that exists in equilibrium with a 4:4 β-hairpin conformation. The adoption of ordered β-hairpin structures for both modified peptides could be confirmed by CD spectroscopy, while SEC/SLS analysis showed a monomeric oligomerization state for all three investigated peptides. With the combination of several NMR methods, we were able to elucidate that even small alterations in the side chain conformation of the proline-glutamate chimera (cis or trans) can significantly influence the conformation of the adopted β-hairpin.

Keywords

Proline chimeraβ-Hairpin conformationβ-TurnConformational analysisCDNMR

Abbreviations

CD

Circular dichroism

HPLC

High performance liquid chromatography

Fmoc

Fluorenylmethoxy carbonyl

AU

Analytical ultracentrifugation

SEC

Size exclusion chromatography

MD

Molecular dynamics

DIC

Diisopropylcarbodiimide

HOBT

1-Hydroxybenzotriazole

HOAT

1-Hydroxy-7-azabenzotriazole

TFA

Trifluoroacetic acid

TIS

Triisopropylsilane

Pcis-E

cis-Proline glutamate chimera

Ptrans-E

trans-proline glutamate chimera

NMR

Nuclear magnetic resonance

1H NMR

Proton nuclear magnetic resonance

COSY

Correlation spectroscopy

TOCSY

Total correlation spectroscopy

NOE

Nuclear Overhauser effect

NOESY

Nuclear Overhauser effect spectroscopy

ROESY

Rotating frame nuclear Overhauser effect spectroscopy

SPPS

Solid phase peptide synthesis

Supplementary material

726_2013_1610_MOESM1_ESM.doc (1.3 mb)
Supplementary material 1 (DOC 1318 kb)

Copyright information

© Springer-Verlag Wien 2013