Packing Structure of Antiparallel ?-Sheet Polyalanine Region in a Sequential Model Peptide of Nephila clavipes Dragline Silk Studied Using 13C Solid-State NMR and MD Simulation.
 

Packing Structure of Antiparallel ?-Sheet Polyalanine Region in a Sequential Model Peptide of Nephila clavipes Dragline Silk Studied Using 13C Solid-State NMR and MD Simulation.

http://www.bionmr.com//www.ncbi.nlm....ed-acspubs.jpg Related Articles Packing Structure of Antiparallel ?-Sheet Polyalanine Region in a Sequential Model Peptide of Nephila clavipes Dragline Silk Studied Using 13C Solid-State NMR and MD Simulation.

Biomacromolecules. 2019 10 14;20(10):3884-3894

Authors: Asakura T, Nishimura A, Aoki A, Naito A

Abstract
Packing structures of polyalanine regions, which are considered to be the reason for the extremely high strength of spider dragline silks, were studied using a series of sequential peptides: (Glu)4GlyGlyLeuGlyGlyGlnGlyAlaGly(Ala)nGlyGlyAlaGl yGlnGlyGlyTyrGlyGly(Glu)4 (n = 3-8) using 13C solid-state NMR spectroscopy. The conformations of (Ala)n in the freeze-dried peptides changed gradually with increasing n from random coils to ?-helices with partial antiparallel ?-sheet (AP-?) structures. Conversely, all the insolubilized peptides, n = 6-8 after low-pH treatment and n = 4-8 after formic acid/methanol treatment, formed AP-? structures with significant amounts of staggered packing arrangements. These results are different from previously obtained results for pure alanine oligopeptides, that is, AP-? (Ala)n formed rectangular packing for less than n = 6 but staggered packings for n >= 7. The 13C-labeled peptides were also used to confirm the staggered packing arrangements from NMR dynamics. Furthermore, a MD simulation supported the observed results.


PMID: 31449407 [PubMed - indexed for MEDLINE]



More...