Disease relevance of SAG1

• An Escherichia coli fusion protein containing 229 amino acids of the AG alpha 1 sequence was recognized by an anti-alpha-agglutinin antibody [1].

High impact information on SAG1

• Mating type-specific agglutination of Saccharomyces cerevisiae a and alpha cells depends on the heterophilic interaction of two cell surface glycoproteins, the gene products of AG alpha 1 and AGA2 [2].
• AG alpha 1 is the structural gene for the Saccharomyces cerevisiae alpha-agglutinin, a cell surface glycoprotein involved in cell-cell interactions during mating [1].
• Sequences similar to the consensus sequences for positive control by MAT alpha 1 and pheromone induction were found upstream of the AG alpha 1 initiation codon [1].
• We have cloned the alpha-agglutinin structural gene, AG alpha 1, by the isolation of alpha-specific agglutination-defective mutants, followed by isolation of a complementing plasmid [1].
• The AG alpha 1 gene could encode a 650-amino-acid protein with a putative signal sequence, 12 possible N-glycosylation sites, and a high proportion of serine and threonine residues, all of which are features expected for the alpha-agglutinin sequence [1].

Biological context of SAG1

• The glycosylated and deglycosylated recombinant SAG1t were recognized by monoclonal and human-serum-derived antibodies, specific for the native SAG1, which suggested that the O-glycosylations had no major effect on the protein conformation [3].
• The conformation of purified Toxoplasma gondii SAG1 antigen, secreted from engineered Pichia pastoris, is adequate for serorecognition and cell proliferation [4].
• Despite incomplete processing and unnatural glycosylation, anchor-less SAG1 proteins apparently adopted a suitable conformation recognized by monoclonal and human serum-derived antibodies, specific for the native SAG1 [4].
• The deduced gene product displays significant identity to Saccharomyces cerevisiae alpha-agglutinin, encoded by AG alpha 1, an adhesion glycoprotein that mediates mating of haploid cells [5].
• While the N- and C-termini of the predicted 1260-amino-acid ALS1 protein resemble those of the 650-amino-acid AG alpha 1, ALS1 contains a central domain of tandem repeats consisting of a highly conserved 36-amino-acid sequence not present in AG alpha 1 [5].

Analytical, diagnostic and therapeutic context of SAG1

• Purification of the anchor-less SAG1 was achieved by a combination of ion-exchange and size-exclusion chromatographies [4].

References