Molina, R. | bioRxiv Science

bioRxiv2020

A collection of designed peptides to target SARS-Cov-2 - ACE2 interaction: PepI-Covid19 database.

The angiotensin-converting enzyme 2 is the cellular receptor used by SARS coronavirus SARS-CoV and SARS-CoV-2 to enter the cell. Both coronavirus use the receptor-binding domain (RBD) of their viral spike protein to interact with ACE2. The structural basis of these interactions are already known, forming a dimer of ACE2 with a trimer of the spike protein, opening the door to target them to prevent the infection. Here we present PepI-Cov19 database, a repository of peptides designed to target the interaction between the RDB of SARS-CoV-2 and ACE2 as well as the dimerization of ACE2 monomers. The peptides were modelled using our method PiPreD that uses native elements of the interaction between the targeted protein and cognate partner that are subsequently included in the designed peptides. These peptides recapitulate stretches of residues present in the native interface plus novel and highly diverse conformations that preserve the key interactions on the interface. PepI-Covid19 database provides an easy and convenient access to this wealth of information to the scientific community with the view of maximizing its potential impact in the development of novel therapeutic agents.

bioinformatics↗

bioRxiv2020

A Zinc-dependent metalloproteinase in the intracellular adaptation of Brucella abortus in macrophages

Brucella abortus is a pathogen that survives in macrophages. Several virulence factors participate in this process, including the open reading frame (ORF) BAB1_0270 codifying of a Zinc-dependent metalloproteinase. Here, its contribution in the process of intracellular adaptation was analyzed by infecting RAW264.7 macrophages with the mutant B. abortus {Delta}270 strain. Results showed that this Zinc-dependent metalloproteinase is a cytoplasmic protein that conforms an operon with a transcriptional regulator, which may constitute a type II toxin-antitoxin system. Functionally, this Zinc-dependent metalloproteinase participated neither in the adherence nor the initial intracellular traffic of B. abortus in macrophages. Nevertheless, its deletion significantly increased the co-localization of B. abortus {Delta}270 with phagolysosomal cathepsin D, reducing both its co-localization with calnexin, present in endoplasmic reticulum derived vesicles, and its intracellular replication within macrophages. Besides, B. abortus {Delta}270-infected macrophages produced significantly higher levels of TNF-, IL-6, CD80 and CD86 than B. abortus 2308, even when several genes involved in virulence (vjbR, hutC, bvrR, virB1) were up-regulated in this mutant. Finally, its deletion significantly reduced the capacity of B. abortus {Delta}270 to adapt, grow and express several virulence factors under acidic conditions. Based on these results, we discuss the role of this Zinc-dependent metalloproteinase in the regulation of the virulence of this pathogen, concluding that it contributes significantly to the intracellular adaptation of B. abortus 2308 during the infection of macrophages. Author summaryBrucella abortus is the causative agent of the brucellosis, a highly contagious diseases. A Zinc-dependent metalloproteinase contributes significantly in the intracellular survival. Here, we demonstrate that this metalloproteinase has homology with ImmA/IrrE proteases, which are involved in the bacterial resistance to hostile environment. Furthermore, it conforms a gene pair with a transcriptional regulator, being required by B. abortus to escape from phagolysosomes, to achieve the endoplasmic reticulum and replicate within macrophages. Its deletion from B. abortus stimulated the macrophages, which produced higher levels of pro-inflammatory cytokines and co-stimulatory proteins. This pathogen showed a reduced ability to adapt and grow under acidic conditions, which would negatively affect its escape from phagolysosomes and consequently, stimulating macrophages. Therefore, this work describes how this Zinc-dependent metalloproteinase significantly contributes in the intracellular adaptation of B. abortus 2308 in macrophages.

microbiology↗