An update on molecular cat allergens: Fel d 1 and what else? Chapter 1: Fel d 1, the major cat allergen

Background: Cats are the major source of indoor inhalant allergens after house dust mites. The global incidence of cat allergies is rising sharply, posing a major public health problem. Ten cat allergens have been identified. The major allergen responsible for symptoms is Fel d 1, a secretoglobin and not a lipocalin, making the cat a special case among mammals. Main body: Given its clinical predominance, it is essential to have a good knowledge of this allergenic fraction, including its basic structure, to understand the new exciting diagnostic and therapeutic applications currently in development. The recent arrival of the component-resolved diagnosis, which uses molecular allergens, represents a unique opportunity to improve our understanding of the disease. Recombinant Fel d 1 is now available for in vitro diagnosis by the anti-Fel d 1 specific IgE assay. The first part of the review will seek to describe the recent advances related to Fel d 1 in terms of positive diagnosis and assessment of disease severity. In daily practice, anti-Fel d 1 IgE tend to replace those directed against the overall extract but is this attitude justified? We will look at the most recent arguments to try to answer this question. In parallel, a second revolution is taking place thanks to molecular engineering, which has allowed the development of various forms of recombinant Fel d 1 and which seeks to modify the immunomodulatory properties of the molecule and thus the clinical history of the disease via various modalities of anti-Fel d 1-specific immunotherapy. We will endeavor to give a clear and practical overview of all these trends

Iron-sulfur repair YtfE protein from Escherichia coli: structural characterization of the di-iron center

YtfE was recently shown to be a newly discovered protein required for the recovery of the activity of iron-sulfur-containing enzymes damaged by oxidative and nitrosative stress conditions. The Escherichia coli YtfE purified protein is a dimer with two iron atoms per monomer and the type and properties of the iron center were investigated by using a combination of resonance Raman and extended X-ray absorption fine structure spectroscopies. The results demonstrate that YtfE contains a non-heme dinuclear iron center having mu-oxo and mu-carboxylate bridging ligands and six histidine residues coordinating the iron ions. This is the first example of a protein from this important class of di-iron proteins to be shown to be involved in the repair of iron-sulfur centers