Development of a universal nanobody-binding Fab module for fiducial-assisted cryo-EM studies of membrane proteins.

ABSTRACT: With conformation-specific nanobodies being used for a wide range of structural, biochemical, and cell biological applications, there is a demand for antigen-binding fragments (Fabs) that specifically and tightly bind these nanobodies without disturbing the nanobody-target protein interaction. Here, we describe the development of a synthetic Fab (termed NabFab) that binds the scaffold of an alpaca-derived nanobody with picomolar affinity. We demonstrate that upon complementary-determining region grafting onto this parent nanobody scaffold, nanobodies recognizing diverse target proteins and derived from llama or camel can cross-react with NabFab without loss of affinity. Using NabFab as a fiducial and size enhancer (50 kDa), we determined the high-resolution cryogenic electron microscopy (c

SUBMITTER: Bloch JS 

PROVIDER: S-EPMC8617411 | biostudies-literature | 2021 Nov

REPOSITORIES: biostudies-literature