Effects of Arginine Deimination and Citrulline Side‐Chain Length on Peptide Secondary Structure Formation. (1st August 2019)

• Record Type: Journal Article
• Authors: Wu, Po‐Yi; Chen, Chin‐Yi; Li, Jhe‐Hao; Lin, Jin‐Kai; Chen, Ting‐Hsuan; Huang, Shing‐Jong; Huang, Shou‐Ling; Cheng, Richard P.
• Is Part Of: Chembiochem. Volume 20:Number 16(2019)
• Page Start: 2118
• Page End: 2124
• Publication Date: 2019-08-01
• Subjects: citrulline -- beta-hairpins -- alpha-helices -- peptides -- protein modifications; Biochemistry -- Periodicals; Molecular biology -- Periodicals; Pharmaceutical chemistry -- Periodicals; 572
• DOI: 10.1002/cbic.201900231
• Languages: English
• ISSNs: 1439-4227

Abstract

Abstract: Post‐translational modifications expand the chemical functionality of peptides and proteins beyond that originating from the encoded amino acids, but studies on the structural effects of these modifications have been limited. Arginine undergoes deimination to give citrulline (Cit), converting the positively charged guanidinium moiety into a neutral urea group. Herein, we report the effect of Arg deimination on secondary structure formation. To understand the reason for the number of methylene units in Cit, the effect of Cit side‐chain length on secondary structure formation was also studied. Ala‐based peptides and β‐hairpin peptides were used to study α‐helix and β‐sheet formation, respectively. Peptides containing Cit analogues were prepared by an orthogonal protecting group strategy coupled with solid‐phase carbamylation. The CD data for the Ala‐based peptides were analyzed by using modified Lifson–Roig theory, showing that the helix propensity of Arg decreased upon deimination and that either shortening or lengthening Cit also decreased the helix propensity. The β‐hairpin peptides were analyzed by NMR methods, showing minimal change in strand formation energetics upon Arg deimination. Altering the Cit side‐chain length did not affect strand formation energetics either. These results should be useful for the preparation of urea‐bearing systems and the design of peptides incorporating urea‐bearing residues with varying side‐chain length. Abstract : Citrullination and secondary structure formation : Arginine deimination (citrullination) converts the positively charged guanidinium moiety into a neutral urea group, disfavoring α‐helix formation but causing minimal change in β‐sheet formation.