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Effect of residue insertion on the stability of polyproline‐I and II structures: Circular dichroism spectroscopic analyses of block‐type oligo‐prolines (Pro)m‐Gly/Ala‐(Pro)n.

Authors :
Kakinoki, Sachiro
Kitamura, Makoto
Noguchi, Yuri
Arichi, Yuki
Source :
Peptide Science. Sep2020, Vol. 112 Issue 5, p1-7. 7p.
Publication Year :
2020

Abstract

The molecular conformation of oligo‐proline peptides composed of two oligo‐proline block sequences and a non‐proline linker residue, designated as (Pro)m‐Gly/Ala‐(Pro)n peptides, was analyzed by circular dichroism (CD) spectroscopy. The CD spectra in water and trifluoroethanol indicated that the two oligo‐proline blocks were separated by an inserted residue independent of polyproline‐II (PP‐II). In addition, the stability of the (Pro)m‐Gly/Ala‐(Pro)n peptides was analyzed using a conformational transition system, during transition from PP‐II to polyproline‐I (PP‐I) in aliphatic alcohols, methanol (MeOH), and 1‐propanol (1‐PrOH). Interestingly, the PP‐II/PP‐I transition was inhibited after a Gly/Ala was inserted at the center of the oligo‐proline; the inhibitory effect of Ala was stronger than that of Gly. When the position of the inserted Ala moved towards the C‐terminal, the (Pro)m‐Gly/Ala‐(Pro)n peptides displayed a PP‐II/PP‐I transition in 1‐PrOH. Our results confirmed that (Pro)m‐Gly/Ala‐(Pro)n peptides prefer to form PP‐II hairpin conformations even in MeOH and 1‐PrOH. Thus, our findings suggest that the insertion of Gly/Ala acts as a stabilizer in PP‐II in proline‐rich peptides. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
24758817
Volume :
112
Issue :
5
Database :
Academic Search Index
Journal :
Peptide Science
Publication Type :
Academic Journal
Accession number :
146081415
Full Text :
https://doi.org/10.1002/pep2.24170