Site-specific relaxation of peptide bond planarity induced by electrically attracted proton/deuteron observed by neutron crystallography

電気的に引き寄せられた陽子・重陽子によって誘起されるペプチド結合平坦性の部位特異的緩和の中性子構造解析による観察

千葉 薫*; 松井 拓郎*; 茶竹 俊行*; 大原 高志   ; 田中 伊知朗*; 油谷 克英*; 新村 信雄*

Chiba, Kaori*; Matsui, Takuro*; Chatake, Toshiyuki*; Ohara, Takashi; Tanaka, Ichiro*; Yutani, Katsuhide*; Niimura, Nobuo*

In structural biology, peptide bonds, fundamental linkages between hundreds of amino acids, of which a protein molecule is composed, have been commonly treated as a plane structure just as Linus Pauling et al. proposed. In this paper, a site-specific peptide bond relaxation mechanism by deuterons whose localization has been suggested by neutron crystallography is proposed. A comprehensive study using X-ray and neutron diffraction and N chemical shifts of individual amide nitrogen atoms within the same peptide bond strongly suggests the relaxation of the electronic resonance structure because of site-specific modulation by protons/deuterons localized on the electron orbital of the carbonyl oxygen.