English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The molecular and crystal structures of two terminally blocked diastereomeric -Pro-Ala-(Aib) 4 - hexapeptide sequences,  p BrBz-L-Pro-D-Ala-(Aib) 4 -O t Bu ( 1 ) and  p BrBz-D-Pro-D-Ala-(Aib) 4 -O t Bu dihydrate ( 2 ), have been determined by X-ray diffraction. The two compounds are characterized by the following parameters: ( 1 ) orthorhombic,  P 2 1 2 1 2 1 ,  a  = 15.827(2) Å,  b  = 22.625(2) Å,  c  = 11.336(2) Å, and  Z  = 4; ( 2 ) triclinic,  P 1,  a  = 10.225(2) Å,  b  = 12.474(2) Å,  c  = 8.827(1) Å,  α  = 104.2(1)°,  β  = 92.8(1)°,  γ  = 85.0(1)°, and  Z  = 1. The structures were solved by direct methods. The least-squares refinements led to  R  values of 0.057 and 0.079 for ( 1 ) and ( 2 ), respectively. The heterochiral L-Pro-D-Ala- sequence of hexapeptide ( 1 ) is folded in a type-II  β -bend conformation, which is followed by a left-handed 3 10 -helix spanning the sequence -D-Ala-(Aib) 3 -. Conversely, the homochiral -D-Pro-D-Ala- sequence of hexapeptide ( 2 ) adopts a distorted type-II′  β -bend conformation, which induces a right-handed 3 10 -helix in the following -D-Ala-(Aib) 3 - sequence. Interestingly, in compound ( 2 ) the D-Ala residue is forced to take a  φ  torsion angle typical of an L-amino acid.

Helical screw sense of peptide molecules. Diastereomeric -Pro-Ala-(Aib) 4 -sequences