Title
Role of Side-Chain and Chirality of the Amino acids on the Supramolecular Assemblies of Dipeptides
Author
Sayanta Roy, Rajat Subhra Giri, Gobinda Dolai, Bhubaneswar Mandal
Year
2020
Journal
Journal of Molecular Structure
Abstract
The supramolecular self-association of alternating L/L and L/D amino acid-containing dipeptides, Boc-L-Ile-L-Phe-OMe (1), Boc-L-Ile-D-Phe-OMe (2), Boc-L-Ile-L-Phg-OMe (3, Phg = phenylglycine), and Boc-L-Ile-D-Phg-OMe (4) have been investigated. The presence of extra methylene (-CH2-) group on the side-chain of C-terminal Phe of 1 causes a significant deviation of molecular arrangements from that of 3. While the molecules in 1 self-assemble to form a single helix-like architecture, the molecules in 3 self-associate around a water molecule to form a cylinder-like structure in the crystalline state. Alternatively, the observed supramolecular arrangements of 2 and 4 are similar, but deviate from that of 1 and 3, due to chirality difference. Peptides 2 and 4 exhibit a discontinued double helix-like structure in the crystalline state. While 1 and 3 self-associate to form helical ribbon-like and nano tube-like structures, respectively, both 2 and 4 form nano rod-like structures in solution.
Instrument
J-1500
Keywords
Circular dichroism, Secondary structure, Biochemistry