Dynamics of Serine-8 Side-Chain in Amyloid-? Fibrils and Fluorenylmethyloxycarbonyl Serine Amino Acid, Investigated by Solid-State Deuteron NMR.
 

Dynamics of Serine-8 Side-Chain in Amyloid-? Fibrils and Fluorenylmethyloxycarbonyl Serine Amino Acid, Investigated by Solid-State Deuteron NMR.

http://www.bionmr.com//www.ncbi.nlm....ed-acspubs.jpg Related Articles Dynamics of Serine-8 Side-Chain in Amyloid-? Fibrils and Fluorenylmethyloxycarbonyl Serine Amino Acid, Investigated by Solid-State Deuteron NMR.

J Phys Chem B. 2020 May 12;:

Authors: Vugmeyster L, Au DF, Ostrovsky D, Rickertsen DRL, Reed SM

Abstract
Serine side-chains are strategic sites of post-translational modifications and it is important to establish benchmarks of their internal dynamics. In this work we compare the dynamics of serine side-chains in several biologically important systems: Serine-8 in the disordered domain of A?(1-40) fibrils in the hydrated and dry states and fluorenylmethyloxycarbonyl(Fmoc) serine with the bulky group that mimics hydrophobicity of the fibrils contacts yet lacks the complexity of the protein system. Using deuterium solid-state NMR static line shape and longitudinal relaxation techniques in the 310 to 180 K temperature range, we compare the main features of the dynamics in these systems. The main motional modes in the fibrils are large-scale fluctuations in the hydrated state of the fibrils, as well as local motions such as 3-site jumps of the C?deuterons at high temperatures and small-angle fluctuations of the C?-C? axis at low temperatures. In the hydrated fibrils two distinct states are present with vastly different extent of large scale diffusive motions and 3-site jumps rate constants. The hydrated state at the physiological conditions is dominated by the "free" state undergoing large-scale diffusive motions and very fast local 3-site jumps, while in the "bound" state these large scale motions are quenched due to transient inter- and intra-molecular interactions. Additionally, in the bound state the 3-site jumps motions are orders of magnitude slower. Details of the dynamics in the serine side-chain are dependent on fine structural features and hydration levels of the systems.


PMID: 32396356 [PubMed - as supplied by publisher]



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