Figure 7
From: Structural and functional insights into the mechanism of action of plant borate transporters
Cryo-EM structure of OsBOR3. (A) CryoEM density map for OsBOR3 shown from the extracellular side of the membrane and the side view looking through the membrane. The dimeric structure of AtBOR1 (individual protomers shown in yellow and red) has been fitted into the OsBOR3 EM density. The additional density around the TM domains corresponds to the LMNG detergent micelle. (B) The respective core and gate domains of the AtBOR1, hNBCe1 and hAE1 monomers fitted into the EM density of OsBOR3 based on the correlation coefficient in Chimera48. A single subunit of each protein was first fitted into the density and then the automatic fitting algorithm in Chimera was used to optimise the fit of the core and gate domains into the density separately. Each protein has been coloured in the same way with blue at the N-terminus through to red at the C-terminus. This image reveals the relative positions of the core and gate domains in the OsBOR3. Superposition of the monomeric AtBOR1 (pink, (C)), hNBCe1 (beige, (D)) and hAE1 (purple, (E)) onto the composite image shown in (B) revealing the OsBOR3 has a conformation most similar to the inward occluded AtBOR1. The images are shown from the side of the protein, looking through the membrane with the extracellular regions of the proteins at the top. The arrows highlight the more open nature of the OsBOR3 on the intracellular side of the membrane compared to hNBCe1 and hAE1.
