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case_images: The pedigree of five patients. The family members were plotted according to the genotype and phenotype, and the detailed mutations were according to the legend
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case_images: PMC6792268_06_40885_2019_128_Fig1_HTML.jpg
case_images: Fig1
case_images: Y329Kfs) het (Fig. 1). The detailed pedigrees of these five families are shown in Fig. 1 and Table 1.  It was reliable, with 83.4% amino acid residues in most favored regions, and 16% in additional allowed regions (Additional file 2: Figures S1&S2).
case_images: The CYP17A1 protein active center before (a) and after (b) amino acid changes. The CYP17A1 protein 3D model was mimicked by a computer. a Normal protein active center of 3D structure. The Van der Waals force between Tyr329 and Leu460 stabilized the protein active center. The region highlighted in orange was the missing part after mutation. b Mutated protein active center of 3D structure. The replacement of Tyr329 by Lys329 caused the loss of protein active center stability
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case_images: PMC6792268_06_40885_2019_128_Fig2_HTML.jpg
case_images: Fig2
case_images: According to the three-dimensional protein model, tyrosine 329 (Tyr329) was located in the center of the J-helix of 17alpha-hydroxylase and formed a hydrophobic portion interacting with the C terminal L460 of the L helix to stabilize the enzymatic structure (Fig. 2a). However, the replacement of Tyr329 by lysine (Lys) led to the loss of 418-503 amino acids, which directly damaged the enzyme active center (Fig. 2b). 
case_images: Ferroheme binding region before and after amino acid changes. a Normal ferroheme binding region in the protein active center. Arg440 and heme formed 2 hydrogen bonds in the protein active center, and Pro434 and Phe453 were essential in stabilizing the beta-fold and J-helix structure around the active center. b Ferroheme binding region in the protein active center after mutation. The Tyr329Lys mutation caused a shortened protein missing the amino acids after 417, which directly damaged the functional region after the ferroheme binding region shifted after losing the hydrogen bond and the upper left shift of preserved Arg409, Ser411 and Val416
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case_images: PMC6792268_06_40885_2019_128_Fig3_HTML.jpg
case_images: Fig3
case_images: Furthermore, we know that the heme binding site (435-455aa) is a pivotal functional region of 17alpha-hydroxylase, in which Arg440 and heme formed 2 hydrogen bonds and Pro434 and Phe453 were essential in stabilizing the beta-fold and J-helix structure around the active center, respectively (Fig. 3a). Nevertheless, the Tyr329Lys mutation caused a shortened protein missing the amino acids after 417, which brought about the loss of the heme binding region (435-455aa) and therefore 17alpha-hydroxylase functional deficiency. (Fig. 3b).