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Lysozyme (Lyz) encoded by phage P1 is required for host cell lysis upon infection. Lyz has a N-terminal Signal Anchor Release (SAR) domain, responsible for its secretion into the periplasm and for its accumulation in a membrane tethered inactive form. Here, we report sequence-specific H, C and N resonance assignments for secreted inactive form of Lyz at pH 4.5. [ABSTRACT FROM AUTHOR]

AbstractWe report the development of an immunotherapeutic molecule, a Humanized immunotoxin, for treating hCG-expressing advanced-stage cancers. PiPP, a high-affinity anti-hCG monoclonal antibody, is used in the immunotoxin for ‘homing’ hCG-positive cancer cells. The deimmunized (DI) form of α-Sarcin, a fungal-origin toxin that lacks functional T-cell epitopes, is used in the design to ensure minimal immunogenicity of the immunotoxin for repetitive use in humans. A single-chain variable fragment (scFv) of PiPP was constructed by linking the Humanized VH and VL regions of the antibody. The scFv part of the antibody was further linked to the toxin α-Sarcin (DI) at the gene level and expressed as a recombinant protein in E. coli. The immunotoxin was purified from the bacterial cell lysate and analysed for binding and cytotoxicity to hCG-secreting colorectal and pancreatic cancer cells. The results showed that the scFv(PiPP)-Sarcin immunotoxin was able to bind to colorectal and pancreatic cancer cells and killed approximately 85% of the cells. In vivo testing of the immunotoxin produced results similar to those of in vitro testing against colorectal adenocarcinoma-induced tumours. This immunotoxin could be a promising immunotherapeutic agent for treating colorectal, pancreatic and other terminal-stage hCG-expressing cancers. [ABSTRACT FROM AUTHOR]

Zinc deficiency is linked to poor prognosis in COVID-19 patients while clinical trials with zinc demonstrate better clinical outcomes. The molecular targets and mechanistic details of the anti-coronaviral activity of zinc remain obscure. We show that zinc not only inhibits the SARS-CoV-2 main protease (Mpro) with nanomolar affinity, but also viral replication. We present the first crystal structure of the Mpro-Zn 2+ complex at 1.9 Å and provide the structural basis of viral replication inhibition. We show that Zn 2+ coordinates with the catalytic dyad at the enzyme active site along with two previously unknown water molecules in a tetrahedral geometry to form a stable inhibited Mpro-Zn 2+ complex. Further, the natural ionophore quercetin increases the anti-viral potency of Zn 2+ . As the catalytic dyad is highly conserved across SARS-CoV, MERS-CoV and all variants of SARS-CoV-2, Zn 2+ mediated inhibition of Mpro may have wider implications.

Lysozyme (Lyz) encoded by phage P1 is required for host cell lysis upon infection. Lyz has a N-terminal Signal Anchor Release (SAR) domain, responsible for its secretion into the periplasm and for its accumulation in a membrane tethered inactive form. Here, we report sequence-specific (1)H, (13)C and (15)N resonance assignments for secreted inactive form of Lyz at pH 4.5.