1KXN

Crystal Structure of Cytochrome c Peroxidase with a Proposed Electron Transfer Pathway Excised to Form a Ligand Binding Channel.

1KXN の概要

• エントリーDOI: 10.2210/pdb1kxn/pdb
• 関連するPDBエントリー: 1CMQ 1KXM
• 分子名称: cytochrome c peroxidase, PROTOPORPHYRIN IX CONTAINING FE (3 entities in total)
• 機能のキーワード: engineered heme channel, oxidoreductase
• 由来する生物種: Saccharomyces cerevisiae (baker's yeast)
• 細胞内の位置: Mitochondrion matrix: P00431
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 33545.07

構造登録者

Rosenfeld, R.J.,Hayes, A.M.A.,Musah, R.A.,Goodin, D.B. (登録日: 2002-02-01, 公開日: 2002-03-06, 最終更新日: 2023-08-16)

主引用文献

Rosenfeld, R.J.,Hays, A.M.,Musah, R.A.,Goodin, D.B.
Excision of a proposed electron transfer pathway in cytochrome c peroxidase and its replacement by a ligand-binding channel.
Protein Sci., 11:1251-1259, 2002

PubMed Abstract: A previously proposed electron transfer (ET) pathway in the heme enzyme cytochrome c peroxidase has been excised from the structure, leaving an open ligand-binding channel in its place. Earlier studies on cavity mutants of this enzyme have revealed structural plasticity in this region of the molecule. Analysis of these structures has allowed the design of a variant in which the specific section of protein backbone representing a previously proposed ET pathway is accurately extracted from the protein. A crystal structure verified the creation of an open channel that overlays the removed segment, extending from the surface of the protein to the heme at the core of the protein. A number of heterocyclic cations were found to bind to the proximal-channel mutant with affinities that can be rationalized based on the structures. It is proposed that small ligands bind more weakly to the proximal-channel mutant than to the W191G cavity due to an increased off rate of the open channel, whereas larger ligands are able to bind to the channel mutant without inducing large conformational changes. The structure of benzimidazole bound to the proximal-channel mutant shows that the ligand accurately overlays the position of the tryptophan radical center that was removed from the wild-type enzyme and displaces four of the eight ordered solvent molecules seen in the empty cavity. Ligand binding also caused a small rearrangement of the redesigned protein loop, perhaps as a result of improved electrostatic interactions with the ligand. The engineered channel offers the potential for introducing synthetic replacements for the removed structure, such as sensitizer-linked substrates. These installed "molecular wires" could be used to rapidly initiate reactions, trap reactive intermediates, or answer unresolved questions about ET pathways.

PubMed: 11967381
DOI: 10.1110/ps.4870102

実験手法

X-RAY DIFFRACTION (1.8 Å)