Fig. 4

LMAN2L three-dimensional structure model. The mutation positions are highlighted by boxes; in the cartoon structure, blue represents the α-helix, purple represents β-folding, and pink coils represent the loop structure. Figure shows the hydrogen bonding observed as a stick structure, where each color represents a different atom, yellow-C atoms, gray-H atoms, blue-N atoms, red-O atoms, or orange-S atoms, and the green dashed line is the hydrogen bond. (A) In the LMAN2L wild type, amino acid 159 is aspartic acid and forms 4 hydrogen bonds with threonine at position 160, tryptophan at position 161, and tyrosine at position 185; (B)in the LMAN2L c.476A>G mutant, amino acid 159 is glycine, and forms 2 hydrogen bonds with tyrosine at position 185, and the number of hydrogen bonds is reduced by 2 compared to that in the wild type, which may affect protein conformation; (C, D) in the human LMAN2L protein predicted changes caused by mutation the p.S354Pfs*29 mutation, amino acid 354 is changed from serine to proline, and the movement of 27 amino acids to encounter a stop codon, may affect protein conformation