3VYM

Dimeric Hydrogenobacter thermophilus cytochrome c552

3VYM の概要

• エントリーDOI: 10.2210/pdb3vym/pdb
• 分子名称: Cytochrome c-552, HEME C (3 entities in total)
• 機能のキーワード: electron transport
• 由来する生物種: Hydrogenobacter thermophilus
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 9204.52

構造登録者

Hayashi, Y.,Nagao, S.,Osuka, H.,Komori, H.,Higuchi, Y.,Hirota, S. (登録日: 2012-09-28, 公開日: 2012-11-07, 最終更新日: 2024-10-09)

主引用文献

Hayashi, Y.,Nagao, S.,Osuka, H.,Komori, H.,Higuchi, Y.,Hirota, S.
Domain Swapping of the Heme and N-Terminal alpha-Helix in Hydrogenobacter thermophilus Cytochrome c(552) Dimer
Biochemistry, 51:8608-8616, 2012

PubMed Abstract: Oxidized horse cytochrome c (cyt c) has been shown to oligomerize by domain swapping its C-terminal helix successively. We show that the structural and thermodynamic properties of dimeric Hydrogenobacter thermophilus (HT) cytochrome c(552) (cyt c(552)) and dimeric horse cyt c are different, although both proteins belong to the cyt c superfamily. Optical absorption and circular dichroism spectra of oxidized dimeric HT cyt c(552) were identical to the corresponding spectra of its monomer. Dimeric HT cyt c(552) exhibited a domain-swapped structure, where the N-terminal α-helix together with the heme was exchanged between protomers. Since a relatively strong H-bond network was formed at the loop around the heme-coordinating Met, the C-terminal α-helix did not dissociate from the rest of the protein in dimeric HT cyt c(552). The packing of the amino acid residues important for thermostability in monomeric HT cyt c(552) were maintained in its dimer, and thus, dimeric HT cyt c(552) exhibited high thermostability. Although the midpoint redox potential shifted from 240 ± 2 to 213 ± 2 mV by dimerization, it was maintained relatively high. Ethanol has been shown to decrease both the activation enthalpy and activation entropy for the dissociation of the dimer to monomers from 140 ± 9 to 110 ± 5 kcal/mol and 310 ± 30 to 270 ± 20 cal/(mol·K), respectively. Enthalpy change for the dissociation of the dimer to monomers was positive (14 ± 2 kcal/mol per protomer unit). These results give new insights into factors governing the swapping region and thermodynamic properties of domain swapping.

PubMed: 23035813
DOI: 10.1021/bi3011303

実験手法

X-RAY DIFFRACTION (2 Å)