Sequence and structure of the rat housekeeping PBG-D isoform.
Porphobilinogen deaminase (PBG-D), a key enzyme in the tetrapyrrole biosynthetic pathway, is encoded by a single gene containing two different promoters. The upstream promoter, found in all cell types, initiates the transcription of the housekeeping PBG-D isoform, whereas the downstream one is erythroid-specific. In this study, we provide the first full sequence of a 1086bp cDNA covering the coding region for the rat ubiquitous PBG-D and its primary amino acid sequence. The cDNA encodes a 39,361 Da protein composed of 361 amino acids. Nucleotide sequence comparison between both isoforms from rat shows similarities of 99.5%, with four changes (C/G) in exon 8 and only one (C/A) in exon 12. Secondary structure prediction reveals that 76.5% of the amino acids from exon 1 are located in a loop. Potential phosphorylation, glycosylation, and myristoylation sites were revealed through motif searches. Housekeeping PBG-D contains coiled-coil segments known to be involved in dynamic rearrangements in the active site.
Cardalda
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CA
(CONICET), Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Buenos Aires, 1428, Argentina.
Batlle
A
A
Juknat
A A
AA
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D018076:DNA, Complementary / Q000737:chemistry; D005091:Exons; D006243:Harderian Gland / Q000201:enzymology; D011163:Hydroxymethylbilane Synthase / Q000737:chemistry* / Q000235:genetics*; D007527:Isoenzymes / Q000737:chemistry* / Q000235:genetics*; D007668:Kidney / Q000201:enzymology; D008099:Liver / Q000201:enzymology; D008297:Male; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D051381:Rats
D018076:DNA, Complementary; D007527:Isoenzymes; D011163:Hydroxymethylbilane Synthase