Panel A: Sequence alignment and Sanger sequencing electropherograms show P S M B 10 variants in control and patient samples across time and fibroblasts. Panel B: Schematic diagram illustrates P S M B 10 gene structure with exons, introns, and protein domains including reported pathogenic variants. Panel C: Multiple sequence alignment compares wild type and G 209 R variant across species, highlighting conserved residues. Panel D: Phylogenetic tree shows evolutionary relationships of proteasomal beta subunit family including P S M B 10 and related paralogs. Panel E: Sequence logo plots display residue conservation around G 209 within P S M B 10 clade and across the broader protein family. Panel F: Protein structure models map residue conservation on P S M B 10 surface showing highly conserved region surrounding G 209.
De novo monoallelic PSMB10 p.G209R private variant is highly conserved and located in an invariant surrounding protein surface. (A) Alignment of the PSMB10 reference sequence (ENST00000358514) with Sanger sequencing electropherograms of PB from a control, PB from the index patient at 6 mo and 3 years of age, and fibroblasts of the index patient. (B) Scheme of the PSMB10 gene with exons (boxes) and introns (beams) and the PSMB10 protein. Pathogenic PSMB10 protein variants reported to cause PRAAS and T lymphopenia are depicted above and below the protein scheme, respectively (not drawn to scale). (C) Multiple sequence alignment of human PSMB10 WT (top row) and PSMB10 G209R (second top row) and its homologs ranging from chimpanzee to frog are shown. (D) Proteasomal β subunit peptidase family ML-based phylogenetic tree indicating separation of paralogs of PSMB10, PSMB7, and others as indicated. The vertebral PSMB10 clade (blue) is part of a larger vertebrate and plant PSMB7 group. (E) PSMB10 sequence and residue conservation LOGO plot surrounding G209 for the PSMB10 clade only (left) and the entire β subunit peptidase family (right) with G209 indicated with an arrowhead. (F) Three rotated views of the PSMB10 structure with residue conservation within the PSMB10 clade mapped on its surface. The cartoon thumbnail image and box indicate the region of PSMB10 shown and the orientation of the center view. Amino acid conservation is displayed with a color gradient as indicated below the structure of cyan (least conserved) to purple (most conserved). The residues surrounding G209 form the most highly conserved region of the protein surface. PB, peripheral blood.