Engineering of a mammalian VMAT2 for cryo-EM analysis results in non-canonical protein folding

Authors: Ying Lyu, Chunting Fu, Haiyun Ma, Zhaoming Su, Ziyi Sun, Xiaoming Zhou

Published: 2024-08-02

DOI: 10.1038/s41467-024-50934-5

Source: Full article

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Abstract

AbstractVesicular monoamine transporter 2 (VMAT2) belongs to the major facilitator superfamily (MFS), and mediates cytoplasmic monoamine packaging into presynaptic vesicles. Here, we present two cryo-EM structures of VMAT2, with a frog VMAT2 adopting a canonical MFS fold and an engineered sheep VMAT2 adopting a non-canonical fold. Both VMAT2 proteins mediate uptake of a selective fluorescent VMAT2 substrate into cells. Molecular docking, substrate binding and transport analysis reveal potential substrate binding mechanism in VMAT2. Meanwhile, caution is advised when interpreting engineered membrane protein structures.