Novel insights into the vancomycin-resistant Enterococcus faecalis (V583) alkylhydroperoxide reductase subunit F

• Published in: Biochimica et biophysica acta. General subjects Vol. 1861; no. 12; pp. 3201 - 3214
• Main Authors: Toh, Yew Kwang, Balakrishna, Asha Manikkoth, Manimekalai, Malathy Sony Subramanian, Chionh, Boon Bin, Seetharaman, Ramya Ramaswamy Chettiyan, Eisenhaber, Frank, Eisenhaber, Birgit, Grüber, Gerhard
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.12.2017
• Subjects: AhpF; Alkylhydroperoxide reductase; Amino Acid Sequence; antibiotic resistance; antioxidant activity; Crystallography, X-Ray; Enterococcus faecalis; Enterococcus faecalis - enzymology; enzyme activity; Escherichia coli; flavoproteins; homeostasis; hosts; Hydrogen peroxide; Models, Molecular; mutation; peroxidase; Peroxiredoxins - chemistry; Protein disulfide oxidoreductases; Protein Domains; Protein Structure, Quaternary; Protein Structure, Tertiary; Protein Subunits; pyridines; Scattering, Small Angle; Thioredoxin-like domain; Vancomycin-Resistant Enterococci - enzymology; Enterococcus faecalis; AhpF; Hydrogen peroxide; EfAhpF; AhpC; NTD_N/C; FAD; Protein disulfide oxidoreductases; EcAhpF; H2O2; Thioredoxin-like domain; CP; CR; SAXS; NADH; PfPDO; AhpR; StAhpF; PDO; Alkylhydroperoxide reductase; CTD:Pyr_redox_2
• ISSN: 0304-4165; 1872-8006
• DOI: 10.1016/j.bbagen.2017.09.011

The ability of the vancomycin-resistant Enterococcus faecalis (V583) to restore redox homeostasis via antioxidant defense mechanism is of importance, and knowledge into this defense is essential to understand its antibiotic-resistance and survival in hosts. The flavoprotein disulfide reductase AhpR, composed of the subunits AhpC and AhpF, represents one such vital part. Circular permutation was found to be a feature of the AhpF protein family. E. faecalis (V583) AhpF (EfAhpF) appears to be a representative of a minor subclass of this family, the typically N-terminal two-fold thioredoxin-like domain (NTD_N/C) is located at the C-terminus, whereas the pyridine nucleotide-disulfide oxidoreductase domain is encoded in the N-terminal part of its sequence. In EfAhpF, these two domains are connected via an unusually long linker region providing optimal communication between both domains. EfAhpF forms a dimer in solution similar to Escherichia coli AhpF. The crystallographic 2.3Å resolution structure of the NTD_N/C domain reveals a unique loop-helix stretch (409ILKDTEPAKELLYGIEKM426) not present in homologue domains of other prokaryotic AhpFs. Deletion of the unique 415PAKELLY421-helix or of 415PAKELL420 affects protein stability or attenuates peroxidase activity. Furthermore, mutation of Y421 is described to be essential for E. faecalis AhpF's optimal NADH-oxidative activity. [Display omitted] •Circular permutation identified in the Enterococcus faecalis AhpF (EfAhpF)•First low-resolution solution structure and flexibility studies of EfAhpF•Crystallographic structure of the catalytic N-terminal domain of EfAhpF•EfAhpF residues identified to be essential for protein stability and activity•Unravelling of a unique linker length of EfAhpF important for enzyme activity