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Biology subjects

Chopra, N.

Publications and source records attributed to Chopra, N..

2 recordsLinked to original sources

Accelerating manufacturing to start large-scale supply of a new adenovirus-vectored vaccine within 100 days

The Coalition for Epidemic Preparedness Innovations 100-day moonshot aspires to launch a new vaccine within 100 days of pathogen identification. Here, we describe work to optimize adenovirus vector manufacturing for rapid response, by minimizing time to clinical trial and first large-scale supply, and maximizing the output from the available manufacturing footprint. We describe a rapid viral seed expansion workflow that allows vaccine release to clinical trials within 60 days of antigen sequence identification, followed by vaccine release from globally distributed sites within a further 40 days. We also describe a new perfusion-based upstream production process, designed to maximize output while retaining simplicity and suitability for existing manufacturing facilities. This improves upstream volumetric productivity of ChAdOx1 nCoV-19 by around four-fold and remains compatible with the existing downstream process, yielding drug substance sufficient for 10000 doses from each liter of bioreactor capacity. Transition to a new production process across a large manufacturing network is a major task. In the short term, the rapid seed generation workflow could be used with the existing production process. We also use techno-economic modelling to show that, if linear scale-up were achieved, a single cleanroom containing two 2000 L bioreactors running our new perfusion-based process could supply bulk drug substance for around 120 million doses each month, costing <0.20 EUR/dose. We estimate that a manufacturing network with 32000 L of bioreactor capacity could release around 1 billion doses of a new vaccine within 130 days of genomic sequencing of a new pathogen, in a hypothetical surge campaign with suitable prior preparation and resources, including adequate fill-and-finish capacity. This accelerated manufacturing process, along with other advantages such as thermal stability, supports the ongoing value of adenovirus-vectored vaccines as a rapidly adaptable and deployable platform for emergency response.

bioengineering↗

The YPhi Motif Defines the Structure-Activity Relationships of Human 20S Proteasome Activators

The 20S proteasome (20S) facilitates turnover of most eukaryotic proteins. Substrate entry into the 20S first requires opening of gating loops through binding of HbYX motifs that are present at the C-termini of certain proteasome activators (PAs). The HbYX motif has been predominantly characterized in the archaeal 20S, whereas little is known about the sequence preferences of the human 20S (h20S). Here, we synthesized and screened [~]120 HbYX-like peptides, revealing unexpected differences from the archaeal system and defining the h20S recognition sequence as the Y-F/Y (Y{Phi}) motif. To gain further insight, we created a functional chimera of the optimized sequence, NLSYYT, fused to the model activator, PA26E102A.A cryo-EM structure of PA26E102A-h20S identified key interactions, including non-canonical contacts and gate-opening mechanisms. Finally, we demonstrated that the Y{Phi} sequence preferences are tuned by valency, allowing multivalent PAs to sample greater sequence space. These results expand the model for termini-mediated gating and provide a template for the design of h20S activators.

biochemistry↗