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NMR studies reveal a novel grab and release mechanism for efficient catalysis of the bacterial 2‐Cys peroxiredoxin machinery
Author(s) -
Nartey Wilson,
Basak Sandip,
Kamariah Neelagandan,
Manimekalai Malathy S. S.,
Robson Scott,
Wagner Gerhard,
Eisenhaber Birgit,
Eisenhaber Frank,
Grüber Gerhard
Publication year - 2015
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/febs.13522
Subject(s) - chemistry , stereochemistry , peroxiredoxin , c terminus , electron transfer , docking (animal) , biochemistry , peroxidase , enzyme , photochemistry , amino acid , medicine , nursing
In bacteria, an ensemble of alkyl hydroperoxide reductase subunits C (AhpC) and F (AhpF) is responsible for scavenging H 2 O 2 . AhpC donates electrons for the reduction of H 2 O 2 , which are provided after NADH oxidation by AhpF. The latter contains an N‐terminal domain ( NTD ), catalyzing the electron transfer from NADH via a FAD of the C‐terminal domain ( CTD ) into AhpC. The NADH ‐bound Escherichia coli AhpF structure revealed that NADH binding brings the substrate to the re ‐face of the FAD , making the Cys–Cys center of the CTD accessible to the NTD disulfide center for electron transfer (Kamariah et al . (2015) Biochim Biophys Acta 1847, 1139–1152). So far insight into the epitope and mechanism of AhpF and AhpC interaction as well as the electron transfer from the NTD to AhpC have been lacking. Here using NMR spectroscopy, we glean insight into the interaction of the NTD of AhpF with AhpC from E. coli . A coordinated disappearance of Ec AhpF NTD peaks was observed in the presence of full length Ec AhpC, indicating a long‐lived AhpC–AhpF complex. C‐terminal truncated Ec AhpC resulted in a more dynamic interaction, revealing specific residue chemical shift perturbation and hence the binding epitope of the complex. Combined with docking studies, we have suggested that the C terminus of AhpC binds to the backside groove of the NTD . In addition, AhpC–AhpF formation is abolished under reducing conditions. We propose for the first time a binding mechanism in which the C terminus of AhpC wraps around the NTD , slowing the dissociation rate for an efficient electron transfer process, and a release mechanism mediated by the conformational change of the C terminus of AhpC upon reduction.