8PBI

Mutant R1617Q of the dihydroorotase domain of human CAD protein bound to the inhibitor fluoroorotate

Summary for 8PBI

• Entry DOI: 10.2210/pdb8pbi/pdb
• Related: 8PBE 8PBG 8PBH 8PBJ 8PBK 8PBM 8PBN 8PBP 8PBQ 8PBR 8PBS 8PBT 8PBU
• Descriptor: CAD protein, 5-FLUORO-2,6-DIOXO-1,2,3,6-TETRAHYDROPYRIMIDINE-4-CARBOXYLIC ACID, FORMIC ACID, ... (5 entities in total)
• Functional Keywords: nucleotide metabolism, de novo pyrimidine synthesis, cad disease, multienzymatic protein, zinc, carboxylated lysine, biosynthetic protein, hydrolase
• Biological source: Homo sapiens (human)
• Total number of polymer chains: 1
• Total formula weight: 40108.34

Authors

del Cano-Ochoa, F.,Ramon-Maiques, S. (deposition date: 2023-06-09, release date: 2023-11-01, Last modification date: 2023-11-22)

Primary citation

Del Cano-Ochoa, F.,Ng, B.G.,Rubio-Del-Campo, A.,Mahajan, S.,Wilson, M.P.,Vilar, M.,Rymen, D.,Sanchez-Pintos, P.,Kenny, J.,Ley Martos, M.,Campos, T.,Wortmann, S.B.,Freeze, H.H.,Ramon-Maiques, S.
Beyond genetics: Deciphering the impact of missense variants in CAD deficiency.
J Inherit Metab Dis, 46:1170-1185, 2023

PubMed Abstract: CAD is a large, 2225 amino acid multienzymatic protein required for de novo pyrimidine biosynthesis. Pathological CAD variants cause a developmental and epileptic encephalopathy which is highly responsive to uridine supplements. CAD deficiency is difficult to diagnose because symptoms are nonspecific, there is no biomarker, and the protein has over 1000 known variants. To improve diagnosis, we assessed the pathogenicity of 20 unreported missense CAD variants using a growth complementation assay that identified 11 pathogenic variants in seven affected individuals; they would benefit from uridine treatment. We also tested nine variants previously reported as pathogenic and confirmed the damaging effect of seven. However, we reclassified two variants as likely benign based on our assay, which is consistent with their long-term follow-up with uridine. We found that several computational methods are unreliable predictors of pathogenic CAD variants, so we extended the functional assay results by studying the impact of pathogenic variants at the protein level. We focused on CAD's dihydroorotase (DHO) domain because it accumulates the largest density of damaging missense changes. The atomic-resolution structures of eight DHO pathogenic variants, combined with functional and molecular dynamics analyses, provided a comprehensive structural and functional understanding of the activity, stability, and oligomerization of CAD's DHO domain. Combining our functional and protein structural analysis can help refine clinical diagnostic workflow for CAD variants in the genomics era.

PubMed: 37540500
DOI: 10.1002/jimd.12667

Experimental method

X-RAY DIFFRACTION (1.5 Å)