Structural and kinetic characterization of mutant human uroporphyrinogen decarboxylases.
Porphyria cutanea tarda (PCT) is caused by inhibition of uroporphyrinogen decarboxylase (URO-D) activity in hepatocytes. Subnormal URO-D activity results in accumulation and urinary excretion of uroporphyrin and heptacarboxyl porphyrin. Heterozygosity for mutations in the URO-D gene is found in the familial form of PCT (F-PCT). Over 70 mutations of URO-D have been described but very few have been characterized structurally. Here we characterize 3 mutations in the URO-D gene found in patients with F-PCT, G318R, K297N, and D306Y. Expression of the D306Y mutation results in an insoluble recombinant protein. G318R and K297N have little effect on the structure or activity of recombinant URO-D, but the proteins display reduced stability in vitro.
Warby
C A
CA
Department of Medicine, University of Utah School of Medicine, Salt Lake City, Utah 84132, USA.
Phillips
J D
JD
Bergonia
H A
HA
Whitby
F G
FG
Hill
C P
CP
Kushner
J P
JP
D000328:Adult; D000368:Aged; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D005260:Female; D005838:Genotype; D006579:Heterozygote; D006801:Humans; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide; D017119:Porphyria Cutanea Tarda / Q000209:etiology / Q000235:genetics; D055550:Protein Stability; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D014575:Uroporphyrinogen Decarboxylase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D011994:Recombinant Proteins; D014575:Uroporphyrinogen Decarboxylase