University of Florence

About: University of Florence is a education organization based out in Florence, Toscana, Italy. It is known for research contribution in the topics: Population & Carbonic anhydrase. The organization has 27292 authors who have published 79599 publications receiving 2341684 citations. The organization is also known as: Università degli studi di Firenze & Universita degli studi di Firenze.

Natural variants of cytotoxic epitopes are T-cell receptor antagonists for antiviral cytotoxic T cells

Abstract: IT has been suggested that mutations within immunodominant cytotoxic T-lymphocyte (CTL) epitopes may be exploited by viruses to evade protective immune responses critical for clearance1–4. Viral escape could originate from passive mechanisms, such as mutations within crucial CTL epitopes, either affecting major histocompatibility complex binding or T-cell antigen receptor (TCR) recognition. Additionally, it has recently been shown that substitutions of TCR contact sites can yield analogue peptides that can still interact with the T-cell receptor but be unable to deliver a full stimulatory signal, thus inducing anergy5 or acting as an antagonist for the TCR6–8. We report here that hepatitis B virus isolates derived from two chronically infected patients display variant epitopes that act as natural TCR antagonists with the capacity to inhibit the CTL response to the wild-type epitope. During natural infection, TCR antagonist mutations of CTL epitopes could contribute to the development of viral persistence, especially if the antiviral CTL response is monospecific or the epitope is strongly immunodominant.

Zinc through the three domains of life.

Abstract: Zinc is one of the metal ions essential for life, as it is required for the proper functioning of a large number of proteins. Despite its importance, the annotation of zinc-binding proteins in gene banks or protein domain databases still has significant room for improvement. In the present work, we compiled a list of known zinc-binding protein domains and of known zinc-binding sequence motifs (zinc-binding patterns), and then used them jointly to analyze the proteome of 57 different organisms to obtain an overview of zinc usage by archaeal, bacterial, and eukaryotic organisms. Zinc-binding proteins are an abundant fraction of these proteomes, ranging between 4% and 10%. The number of zinc-binding proteins correlates linearly with the total number of proteins encoded by the genome of an organism, but the proportionality constant of Eukaryota (8.8%) is significantly higher than that observed in Bacteria and Archaea (from 5% to 6%). Most of this enrichment is due to the larger portfolio of regulatory proteins in Eukaryota.