Glycan microarray analysis of Candida glabrata adhesin ligand specificity.
The Candida glabrata genome encodes at least 23 members of the EPA (epithelial adhesin) family responsible for mediating adherence to host cells. To better understand the mechanism by which the Epa proteins contribute to pathogenesis, we have used glycan microarray analysis to characterize their carbohydrate-binding specificities. Using Saccharomyces cerevisiae strains surface-expressing the N-terminal ligand-binding domain of the Epa proteins, we found that the three Epa family members functionally identified as adhesins in Candida glabrata (Epa1, Epa6 and Epa7) bind to ligands containing a terminal galactose residue. However, the specificity of the three proteins for glycans within this class varies, with Epa6 having a broader specificity range than Epa1 or Epa7. This result is intriguing given the close homology between Epa6 and Epa7, which are 92% identical at the amino acid level. We have mapped a five-amino-acid region within the N-terminal ligand-binding domain that accounts for the difference in specificity of Epa6 and Epa7 and show that these residues contribute to adherence to both epithelial and endothelial cell lines in vitro.
Zupancic
Margaret L
ML
Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
Frieman
Matthew
M
Smith
David
D
Alvarez
Richard A
RA
Cummings
Richard D
RD
Cormack
Brendan P
BP
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D041221:Candida glabrata / Q000737:chemistry / Q000378:metabolism*; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000737:chemistry / Q000378:metabolism; D002460:Cell Line; D042783:Endothelial Cells / Q000378:metabolism / Q000382:microbiology; D005656:Fungal Proteins / Q000737:chemistry* / Q000378:metabolism*; D006168:Guinea Pigs; D054884:Host-Pathogen Interactions; D008024:Ligands; D008969:Molecular Sequence Data; D011134:Polysaccharides / Q000378:metabolism*; D040081:Protein Array Analysis; D011485:Protein Binding; D025941:Protein Interaction Mapping; D017434:Protein Structure, Tertiary; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013329:Structure-Activity Relationship
D015815:Cell Adhesion Molecules; D005656:Fungal Proteins; D008024:Ligands; D011134:Polysaccharides