标题：3_(10)-Helical Peptide Acting as a Dual Relay for Charge-Hopping Transfer in Proteins
作者：Meng Zhang;Jing Zhao;Hongfang Yang
作者机构：[Zhang, M] School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China;[ Zhao, J] School of Chemistry and Chemical Engineer 更多
通讯作者地址：[Bu, YX]Shandong Univ, Sch Chem & Chem Engn, Jinan 250100, Peoples R China.
来源：The journal of physical chemistry, B. Condensed matter, materials, surfaces, interfaces & biophysical
摘要：We present a density functional calculational study to clarify that a 3_(10)-helix peptide can serve as a novel dual-relay element to mediate long-range charge migrations via its C- and N-termini in proteins. The ionization potential of the 3_(10)-helix C-terminus correlates inversely with the helix length, HOMO energy, and dipole moment. In particular, it decreases considerably with the increase in the number of peptide units, even to a smaller value than that of the easily oxidized amino acid residue, which implies the possibility of releasing an electron and forming a hole at the 3_(10)-helical C-terminus. On the other hand, the electron affinity of the 3_(10)-helical N- terminus correlates positively with the helix length and dipole moment but inversely with the LUMO energy. Clearly, the increasing positive electron-binding energy with the increase in the number of peptide units implies that the 3_(10)-helical N-terminus can capture an excess electron and play an electron-relaying role. The relaying ability of the 3_(10)-helical C-terminus and N-terminus not only depends on the helix length but also varies subject to the capping effect, the collaboration and competition of proximal groups, and solvent environments. In contrast to the known hole relays such as the side chains of Tyr and Trp and electron relays such as the side chains of protonated Lys and Arg, either the hole relay (the 3_(10)-helix C-terminus) or the electron relay (the 3_(10)-helix N-terminus) is property-tunable and could apply to different proteins in assisting or mediating long-range charge migrations.