De novo design, synthesis, and function of semiartificial myoglobin conjugated with coiled-coil two-α-helix peptides

Seiji Sakamoto, Atsushi Ito, Kazuaki Kudo, Susumu Yoshikawa

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)

Abstract

The introduction of a flavin chromophore on the myoglobin (Mb) surface and an effective electron-transfer (ET) reaction through the flavin were successfully achieved by utilizing the self-assembly of heterostranded coiled-coil peptides. We have prepared a semiartificial Mb, named Mb-1αK, in which an amphiphilic and cationic α-helix peptide is conjugated at the heme propionate (Heme-1αK). Heme-1αK has a covalently bound iron-protoporphyrin IX (heme) at the N terminus of a 1αK peptide sequence. This sequence was designed to form a heterostranded coiled-coil in the presence of a counterpart amphiphilic and anionic 1αE peptide sequence in a parallel orientation. Two peptides, Fla1-1αE and Fla 31-1αE, both incorporating a 10-methylisoalloxazine moiety as an artificial flavin molecule, were also prepared (Fla = 2-[7-(10-methyl) isoalloxazinyl]-2-oxoethyl). Heme-1αK was successfully inserted into apomyoglobin to give Mb-1αK. Mb-1αK recognized the flavin-modified peptides and a two-a-helix structure was formed. In addition, an efficient ET from reduced nicotinamide adenine dinucleotide to the heme center through the flavin unit was observed. The ET rate was faster in the presence of Fla 1-1αE than in the presence of Fla31-1αE or the equivalent molecule that has no peptide chain. These results demonstrate that the introduction of a functional chromophore on the Mb surface can be achieved by using specific peptide-peptide interactions. Moreover, the dependence of the ET rate on the position of the flavin indicated that the distance between the heme active site and the flavin chromophore was regulated by the three-dimensional structure of the designed polypeptide.

Original languageEnglish
Pages (from-to)3717-3726
Number of pages10
JournalChemistry - A European Journal
Volume10
Issue number15
DOIs
Publication statusPublished - 2004 Aug 6

Keywords

  • Chromophores
  • Electron transfer
  • Helical structures
  • Heme proteins
  • Myoglobin

ASJC Scopus subject areas

  • Catalysis
  • Organic Chemistry

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