Synthetic AChE function using organophosphate-resistant protein-nucleic acid conjugates
Abstract
Organophosphorous (OP) poisoning can result from exposure to either chemical weapons or agrochemicals, and thus poses a significant health threat to both warfighters and civilians. OP agents covalently inhibit acetylcholinesterase (AChE), leading to a buildup of acetylcholine (ACh), which overstimulates the ACh receptor. Current treatments focus on blocking the Ach receptor or reactivating AChE, but the efficacy of these treatments is limited. In contrast, Nature has found a more successful approach, as insects have evolved to tolerate OP insecticides via overexpression of AChE or mutation of AChE to reduce OP susceptibility. Using this inspiration from Nature, we hypothesize that augmenting AChE function using synthetic OP-resistant enzymes could represent a viable alternative approach for treatment of OP poisoning in humans. In the proposed research, we will investigate both DNA- and protein-based catalysts as platforms for OP-resistant AChE activity. We will also explore the fundamental scientific question of whether catalytic efficiency can be enhanced by using an affinity reagent to pre-concentrate the substrate in proximity to the catalyst (Figure 1). As a centerpiece of the proposal, we will utilize virus-like particles (VLPs), which are biologically-derived hollow protein nanoparticles, as a scaffold for assembly of the catalysts and affinity reagents. The key strategic advantages of this approach are that: (1) VLPs have pores of sufficient size to enable diffusion of ACh into their interior, but exclude nucleases and proteases, thus providing biostability to the encapsulated catalysts and affinity reagents; (2) VLPs can be expressed in high yield from bacterial cell culture and assembled in vitro with a number of different molecular cargoes; (3) VLPs are multimeric assemblies having many copies of the same protein(s), enabling controlled multivalent encapsulation of catalysts and affinity reagents; (4) VLPs can be easily functionalized, enabling the attachment of ligands to promote receptor-mediated uptake into the central nervous system (CNS), where ACh accumulation is most problematic. Together, this research will explore a new approach to treating OP poisoning while contributing fundamental knowledge to the fields of biomolecular assembly, evolution, and function.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 16, 2019
- Source ID
- HDTRA11810029
Entities
People
- Jennifer M. Heemstra
Organizations
- Defense Threat Reduction Agency
- Emory University