RESUMO
Blocking the association between the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein receptor-binding domain (RBD) and the human angiotensin-converting enzyme 2 (ACE2) is an attractive therapeutic approach to prevent the virus from entering human cells. While antibodies and other modalities have been developed to this end, d-amino acid peptides offer unique advantages, including serum stability, low immunogenicity, and low cost of production. Here, we designed potent novel D-peptide inhibitors that mimic the ACE2 α1-binding helix by searching a mirror-image version of the PDB. The two best designs bound the RBD with affinities of 29 and 31 nM and blocked the infection of Vero cells by SARS-CoV-2 with IC50 values of 5.76 and 6.56 µM, respectively. Notably, both D-peptides neutralized with a similar potency the infection of two variants of concern: B.1.1.7 and B.1.351 in vitro. These potent D-peptide inhibitors are promising lead candidates for developing SARS-CoV-2 prophylactic or therapeutic treatments.
Assuntos
Peptídeos , SARS-CoV-2 , Animais , Chlorocebus aethiops , Simulação de Acoplamento Molecular , Células VeroRESUMO
Chrysotila dentata is an ecologically important marine alga contributing to the coccolith formation. In this study, a complete chloroplast (cp DNA) genome of Chrysotila dentata was sequenced by using Illumina Hiseq and was analyzed with the help of a bioinformatics tool CPGAVAS2. The circular chloroplast genome of Chrysotila dentata has a size of 109,017 bp with two inverted repeats (IRs) regions (4513 bp each) which is a common feature in most land plants and algal species. The Chrysotila dentata cp genome consists of 61 identified protein-coding genes, 30 tRNA genes and 6 rRNAs with 21 microsatellites. The phylogenetic relationship with other select algal species revealed a close phylogeny of Chrysotila dentata with Phaeocystis antarctica. This is the first report of the cp genome analysis of genus Chrysotila and the results from this study will be helpful for understanding the genetic structure and function of chloroplast in other species of Chrysotila.
Assuntos
Cloroplastos/genética , Haptófitas/genética , Biologia Computacional/métodos , Evolução Molecular , Genes de Plantas , Genoma , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Sequências Repetidas Invertidas/genética , Repetições de Microssatélites/genética , Filogenia , RNA Ribossômico/genética , Análise de Sequência de DNA/métodos , Sequenciamento Completo do Genoma/métodosRESUMO
Seventeen bacterial isolates were screened for their cellulase activity by carboxymethyl cellulose (CMC) plate assay. The bacterial strain K1 showed the largest depolymerized region in CMC plate assay and was further studied for quantitative cellulase activity. On the basis of 16S rDNA sequence analysis, the strain K1 was found to be Bacillus sp. This strain produced the maximum CMCase at pH 6 and 50 °C in the presence of peptone (1%) as a source of nitrogen. The CMCase activity was stimulated by Ca(2+) (2 mM) by 20% over the control. The CMCase activity of this Bacillus sp. K1 was highly induced when lactose was used as a source of carbon during fermentation.