13C multiplet nuclear magnetic resonance relaxation-derived ring puckering and backbone dynamics in proline-containing glycine-based peptides

D. Mikhailov, V. A. Daragan, Kevin H Mayo

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

13CH2-multiplet nuclear magnetic resonance relaxation studies on proline (P)-containing glycine (G)-based peptides, GP, PG, GPG, PGG, and GPGG, provided numerous dipolar auto- and cross-correlation times for various motional model analyses of backbone and proline-ring bond rotations. Molecular dynamics simulations and bond rotation energy profiles were calculated to assess which motions could contribute most to observed relaxation phenomena. Results indicate that proline restricts backbone psi 1, psi 2, and phi 2 motions by 50% relative to those found for a polyglycine control peptide. psi 1 rotations are more restricted in the trans-proline isomer state than in the cis form. A two-state jump model best approximates proline ring puckering which in water could occur either by the C gamma endo-exo or by the C2 interconversion mechanism. The temperature dependence (5 degrees to 75 degrees C) of C beta, and C gamma, and C delta angular changes is rather flat, suggesting a near zero enthalpic contribution to the ring puckering process. In lower dielectric solvents, dimethylsulfoxide and methanol, which may mimic the hydrophobic environment within a protein, the endo-exo mechanism is preferred.

Original languageEnglish (US)
Pages (from-to)1540-1550
Number of pages11
JournalBiophysical journal
Volume68
Issue number4
DOIs
StatePublished - 1995

Bibliographical note

Funding Information:
This research was supported by National Science Foundation grant MCB-9420203. We are grateful to Marek Kloczewiak for the synthesis of peptides GP, PG, and GPG. NMR experiments were performed at the University of Minnesota High Field-NMR Laboratory.

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