5B51

Crystal structure of heme binding protein HmuT R242A mutant

5B51 の概要

• エントリーDOI: 10.2210/pdb5b51/pdb
• 関連するPDBエントリー: 5B4Z 5B50 5az3
• 分子名称: ABC-type transporter, periplasmic component, PROTOPORPHYRIN IX CONTAINING FE (3 entities in total)
• 機能のキーワード: heme, abc transporter, transport protein
• 由来する生物種: Corynebacterium glutamicum ATCC 13032
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 36677.60

構造登録者

Muraki, N.,Aono, S. (登録日: 2016-04-20, 公開日: 2017-03-01, 最終更新日: 2023-11-08)

主引用文献

Muraki, N.,Kitatsuji, C.,Ogura, M.,Uchida, T.,Ishimori, K.,Aono, S.
Structural Characterization of Heme Environmental Mutants of CgHmuT that Shuttles Heme Molecules to Heme Transporters
Int J Mol Sci, 17:-, 2016

PubMed Abstract: Corynebacteria contain a heme uptake system encoded in hmuTUV genes, in which HmuT protein acts as a heme binding protein to transport heme to the cognate transporter HmuUV. The crystal structure of HmuT from Corynebacterium glutamicum (CgHmuT) reveals that heme is accommodated in the central cleft with His141 and Tyr240 as the axial ligands and that Tyr240 forms a hydrogen bond with Arg242. In this work, the crystal structures of H141A, Y240A, and R242A mutants were determined to understand the role of these residues for the heme binding of CgHmuT. Overall and heme environmental structures of these mutants were similar to those of the wild type, suggesting that there is little conformational change in the heme-binding cleft during heme transport reaction with binding and the dissociation of heme. A loss of one axial ligand or the hydrogen bonding interaction with Tyr240 resulted in an increase in the redox potential of the heme for CgHmuT to be reduced by dithionite, though the wild type was not reduced under physiological conditions. These results suggest that the heme environmental structure stabilizes the ferric heme binding in CgHmuT, which will be responsible for efficient heme uptake under aerobic conditions where Corynebacteria grow.

PubMed: 27240352
DOI: 10.3390/ijms17060829

実験手法

X-RAY DIFFRACTION (1.3 Å)