Structure, mechanism and ensemble formation of the alkylhydroperoxide reductase subunits AhpC and AhpF from Escherichia coli.
Hydroperoxides are reactive oxygen species (ROS) that are toxic to all cells and must be converted into the corresponding alcohols to alleviate oxidative stress. In Escherichia coli, the enzyme primarily responsible for this reaction is alkylhydroperoxide reductase (AhpR). Here, the crystal structures of both of the subunits of EcAhpR, EcAhpF (57 kDa) and EcAhpC (21 kDa), have been solved. The EcAhpF structures (2.0 and 2.65 Å resolution) reveal an open and elongated conformation, while that of EcAhpC (3.3 Å resolution) forms a decameric ring. Solution X-ray scattering analysis of EcAhpF unravels the flexibility of its N-terminal domain, and its binding to EcAhpC was demonstrated by isothermal titration calorimetry. These studies suggest a novel overall mechanistic model of AhpR as a hydroperoxide scavenger, in which the dimeric, extended AhpF prefers complex formation with the AhpC ring to accelerate the catalytic activity and thus to increase the chance of rescuing the cell from ROS.
School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore.
Phat Vinh
PV
Dip
Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, #07-01 Matrix, Singapore 138671, Singapore.
Neelagandan
N
Kamariah
School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore.
Malathy Sony
MS
Subramanian Manimekalai
School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore.
Wilson
W
Nartey
School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore.
Asha Manikkoth
AM
Balakrishna
Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, #07-01 Matrix, Singapore 138671, Singapore.
Frank
F
Eisenhaber
Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, #07-01 Matrix, Singapore 138671, Singapore.
Birgit
B
Eisenhaber
School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore.
Gerhard
G
Grüber
D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000737:chemistry* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D054464:Peroxiredoxins / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation; D017382:Reactive Oxygen Species / Q000378:metabolism
D029968:Escherichia coli Proteins; D017382:Reactive Oxygen Species; D054464:Peroxiredoxins; C515937:ahpC protein, E coli; C515938:ahpF protein, E coli
alkylhydroperoxide reductase; oxidative stress; peroxiredoxin reductase; reactive oxygen species; redox homeostasis