Warning: This is a preliminary report that has not been peer-reviewed. It should not be regarded as conclusive, guide clinical practice/health-related behavior, or be reported in news media as established information.

Xu Y, Zheng R, Prasad A, Liu M, Wan Z, Zhou X, Porter RM, Sample M, Poppleton E, Procyk J, Liu H, Li Y, Wang S, Yan H, Sulc P, Stephanopoulos N

Multivalency enables nanostructures to bind molecular targets with high affinity. Although antibodies can be generated against a wide range of antigens, their shape and size cannot be tuned to match a given target. DNA nanotechnology provides an attractive approach for designing customized multivalent scaffolds due to the addressability and programmability ...

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of the nanostructure shape and size. Here, we design a nanoscale synthetic antibody (nano-synbody) based on a three-helix bundle DNA nanostructure with one, two, or three identical arms terminating in a mini-binder protein that targets the SARS-CoV-2 spike protein. The nano-synbody was designed to match the valence and distance between the three receptor binding domains (RBDs) in the spike trimer, in order to enhance affinity. The protein-DNA nano-synbody shows tight binding to the wild-type, Delta, and several Omicron variants of the SARS-CoV-2 spike trimer, with affinity increasing as the number of arms increases from one to three. The effectiveness of the nano-synbody was also verified using a pseudovirus neutralization assay, with the three-arm nanostructure inhibiting two Omicron variants against which the structures with only one or two arms are ineffective. The structure of the three-arm nano-synbody bound to the Omicron variant spike trimer was solved by negative-stain transmission electron microscopy reconstruction, and shows the protein-DNA nanostructure with all three arms attached to the RBD domains, confirming the intended trivalent attachment. The ability to tune the size and shape of the nano-synbody, as well as its potential ability to attach two or more different binding ligands, will enable the high-affinity targeting of a range of proteins not possible with traditional antibodies.

Date: Sep. 19, 2023

Status: Preliminary Report

View Source: doi: 10.1101/2023.09.18.558353

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