Structure and Dynamics of Two Elastin-like Polypentapeptides Studied by NMR Spectroscopy

Abstract

The structure and dynamics of two synthetic elastin-like polypentapeptides, poly(G(1)V(1)G(2)V(2)P) and poly(AV(1)GV(2)P), were studied in D(2)O and H(2)O at various temperatures by using (1)H, (2)H,(13)C, and (15)N NMR spectra, relaxations, and PGSE self-diffusivity measurement. Signal assignments were made using COSY, NOESY, HXCORR, HSQC, HMBC, and SSLR INEPT techniques. Temperature-induced conformation changes were studied using (3)J(NHCH) couplings, NOESY connectivity, chemical shifts, and signal intensities. Hydrodynamic radii were derived from self-diffusion coefficients measured by the pulsed-gradient spin-echo (PGSE) method. Selective hydration (hydrophilic or hydrophobic) was explored using NOESY and ROESY spectral methods and longitudinal and transverse (1)H relaxation of HOD and quadrupolar (2)H relaxation of D(2)O. Four different physical states were discerned in different temperature regions for both polymers: state I of a rather extended, statistically shaped and fully hydrated polymer below the critical temperature (approximately 299-300 K); state II, a relatively coiled and globular but disordered preaggregation state, developing in a rather narrow region, 300-303 K, in the case of poly(AV(1)GV(2)P) and in a broader region, overlapping with the next one, in poly(G(1)V(1)G(2)V(2)P); state III, a tightly coiled, more compact state in the region 303-313 K; and, finally, state IV, an aggregated (and eventually flocculating and sedimenting) state beyond 313 K. States II-IV coexist in varying proportions in the whole temperature range above 299 K. A structure characterized by a beta-turn stabilized by H-bonding between the Ala carbonyl and Val(2) NH groups of poly(AV(1)GV(2)P) was detected by NOESY just above the transition temperature. States II and III are progressively more stripped of their hydration sheath but retain some molecules of water confined and relatively immobilized in their coils.

Resolving Nitrogen-15 and Proton Chemical Shifts for Mobile Segments of Elastin with Two-dimensional NMR Spectroscopy

“…Peak 4 directly corresponds to the 110.7 ppm resonance observed at 37°C in the one-dimensional experiments. The glycine that neighbors valine, denoted as VG, has a 15 N chemical shift of 110 -111 ppm in the elastin mimetics (32). Valines generally induce a downfield shift, compared with the neighboring effects of Ala, Pro, and Gly (34).…”

Conformational Dynamics of Minimal Elastin‐Like Polypeptides: The Role of Proline Revealed by Molecular Dynamics and Nuclear Magnetic Resonance

“…[2] Despite many efforts, the structural information obtained by using various methods-including nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR), Raman, circular dichroism (CD), and X-ray, see for example, refs. [2][3][4][5][6][7][8] and references therein-remains severely limited because of the extreme insolubility of the mature cross-linked form of elastin and the high mobility of the elastin backbone. These methods do, however, suggest that turns, especially b-and g-turns, are the main local secondary-structural features of elastin-like peptides (ELPs).…”

“…G (8) )-NHCH 3 , with the proline residue in a trans conformation, and the wt ELP with the proline residue in a cis conformation, were carried out at nine different temperatures (i.e. 300, 310, 320, 330, 340, 350, 360, 380, and 400 K).…”

Aggregation behaviour of biohybrid microgels from elastin-like recombinamers

“…However, the signals in the aliphatic region of Gly 1 and Gly 2 as well as Val 1 and Val 2 cannot be resolved under MAS conditions. 10,17,22 Morphology and the effect of cross-link density of ELR microgels by 1 …”

“…13,14 Such a type of aggregation is also present in recombinantly expressed human elastin polypeptides, as well as polypentapeptides and was shown to be mainly due to interactions between the hydrophobic domains. [14][15][16][17][18] Besides the aggregation investigation of polypeptide biopolymers, the study of this process for the synthesis of thermally responsive nanoparticles from genetically encoded peptide polymers for loading hydrophobic drugs was also reported. 19,20 A novel class of elastin like doublehydrophobic block polypeptides comprising proline-rich and a DWI-Leibniz-Institute for Interactive Materials, e.V., RWTH-Aachen University, glycine-rich segments have been studied showing the selfassembly of thermoresponsive nanofibers.…”