Fig. 1

Structures of the human bridge-like lipid transfer protein (BLTP) superfamily members. A Ribbon models of the predicted structure of representative members of the human bridge-like lipid transfer protein (BLTP) superfamily. Repeating β-groove (RBG) domains are alternately labelled in pink, orange, and blue; the VAB domain of VPS13C [17,18,19] is shown in grey, and the ATG_C and PH domains [13] are shown in teal. Note that the positioning of these domains in VPS13C relative to the hydrophobic groove has not been experimentally determined. Large unstructured loops have been omitted from BLTP1, BLTP3B and ATG2A for visual clarity. HGNC approved symbols (in bold) are used for the encoded proteins; previous symbols/aliases are in parentheses. B Sphere model showing a cross-section of BLTP2 with carbon atoms (grey), oxygen (red), nitrogen (blue), and sulphur (yellow). Note the presence of an inner hydrophobic groove ideal for transport of lipids. The predicted structures of BLTP2, BLTP3B and ATG2A were downloaded from the AlphaFold database [12]. The VPS13C structure was generated using trRosetta [14] following the protocol described in [17]. The BLTP1 structure was generated by using trRosetta [14] to fold seven ~ 1500 amino acid overlapping fragments of the protein; these fragments were then assembled using the matchmaker command with Needleman-Wunsch global alignment in ChimeraX v.1.4 [20]. All ribbon models were coloured and rendered using PyMOL v.2.4.0; sphere model rendered using ChimeraX v.1.4 [20]