Infrared study of synthetic peptide analogues of the calcium‐binding site III of troponin C: The role of helix F of an EF‐hand motif1. Issue 5 (20th February 2013)

• Record Type: Journal Article
• Authors: Nara, Masayuki; Morii, Hisayuki; Tanokura, Masaru
• Is Part Of: Biopolymers. Volume 99:Issue 5(2012)
• Page Start: 342
• Page End: 347
• Publication Date: 2013-02-20
• Subjects: Biopolymers -- Periodicals; Peptides -- Periodicals; Spectrum analysis -- Periodicals; 572.33
• DOI: 10.1002/bip.22176
• Languages: English
• ISSNs: 0006-3525

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>The EF‐hand motif (helix–loop–helix) is a Ca²⁺‐binding domain that is common among many intracellular Ca²⁺‐binding proteins. We applied Fourier‐transform infrared spectroscopy to study the synthetic peptide analogues of site III of rabbit skeletal muscle troponin C (helix E–loop–helix F). The 17‐residue peptides corresponding to loop–helix F (DRDADGYIDAEELAEIF), where one residue is substituted by the <sc>D</sc>‐type amino acid, were investigated to disturb the α‐helical conformation of helix F systematically. These <sc>D</sc>‐type‐substituted peptides showed no band at about 1555 cm⁻¹ even in the Ca²⁺‐loaded state although the native peptide (<sc>L</sc>‐type only) showed a band at about 1555 cm⁻¹ in the Ca²⁺‐loaded state, which is assigned to the side‐chain COO⁻ group of Glu at the 12th position, serving as the ligand for Ca²⁺ in the bidentate coordination mode. Therefore, helix F is vital to the interaction between the Ca²⁺ and the side‐chain COO⁻ group of Glu at the 12th position. Implications of the COO⁻ antisymmetric stretch and the amide‐I′ of the synthetic peptide analogues of the Ca²⁺‐binding sites are discussed. © 2012 Wiley Periodicals, Inc. Biopolymers 99: 342–347, 2013.</p> </abstract>