Fabry disease: isolation of a cDNA clone encoding human alpha-galactosidase A.
Fabry disease is an X-linked inborn error of metabolism resulting from the deficient activity of the lysosomal hydrolase, alpha-galactosidase A (alpha-Gal A; alpha-D-galactoside galactohydrolase, EC 3.2.1.22). To investigate the structure, organization, and expression of alpha-Gal A, as well as the nature of mutations in Fabry disease, a clone encoding human alpha-Gal A was isolated from a lambda gt11 human liver cDNA expression library. To facilitate screening, an improved affinity purification procedure was used to obtain sufficient homogeneous enzyme for production of monospecific antibodies and for amino-terminal and peptide microsequencing. On the basis of an amino-terminal sequence of 24 residues, two sets of oligonucleotide mixtures were synthesized corresponding to adjacent, but not overlapping, amino acid sequences. In addition, an oligonucleotide mixture was synthesized based on a sequence derived from an alpha-Gal A internal tryptic peptide isolated by reversed-phase HPLC. Four positive clones were initially identified by antibody screening of 1.4 X 10(7) plaques. Of these, only one clone (designated lambda AG18) demonstrated both antibody binding specificity by competition studies using homogeneous enzyme and specific hybridization to synthetic oligonucleotide mixtures corresponding to amino-terminal and internal amino acid sequences. Nucleotide sequencing of the 5' end of the 1250-base-pair EcoRI insert of clone lambda AG18 revealed an exact correspondence between the predicted and known amino-terminal amino acid sequence. The insert of clone lambda AG18 appears to contain the full-length coding region of the processed, enzymatically active alpha-Gal A, as well as sequences coding for five amino acids of the amino-terminal propeptide, which is posttranslationally cleaved during enzyme maturation.
D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000276:immunology; D002846:Chromatography, Affinity; D003360:Cosmids; D004247:DNA / Q000302:isolation & purification; D000795:Fabry Disease / Q000201:enzymology / Q000235:genetics*; D005696:Galactosidases / Q000235:genetics*; D006801:Humans; D008099:Liver / Q000032:analysis; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology; D000519:alpha-Galactosidase / Q000235:genetics* / Q000276:immunology
D000911:Antibodies, Monoclonal; D011994:Recombinant Proteins; D004247:DNA; D005696:Galactosidases; D000519:alpha-Galactosidase