Candida albicans Als adhesins have conserved amyloid-forming sequences.
The cell wall-bound Als adhesins of Candida albicans mediate both yeast-to-host tissue adherence and yeast aggregation. This aggregation is amyloid-like, with self-propagating secondary-structure changes, amyloid-characteristic dye binding, and induced birefringence (J. M. Rauceo, N. K. Gaur, K. G. Lee, J. E. Edwards, S. A. Klotz, and P. N. Lipke, Infect. Immun. 72:4948-4955, 2004). Therefore, we determined whether Als proteins could form amyloid fibers with properties like those in cellular aggregation. The beta-aggregation predictor TANGO identified a heptapeptide sequence present in a highly conserved sequence with amyloid-forming potential in Als1p, Als3p, and Als5p. A tridecapeptide containing this sequence formed fibers that bound Congo red and thioflavin T and had characteristic amyloid morphology. Als5p(20-431) and Als5p(20-664), large fragments of Als5p containing the amyloid sequence, also formed amyloid-like fibers and bound Congo red under native conditions. K(a)/K(s) analysis showed that the amyloid-forming sequences are highly conserved in Als proteins and evolve more slowly than other regions of the proteins. Therefore, amyloid-forming ability itself is conserved in these proteins.
Otoo
Henry N
HN
Department of Biology, Brooklyn College, 2900 Bedford Avenue, Brooklyn, NY 11210, USA.
Lee
Kyeng Gea
KG
Qiu
Weigang
W
Lipke
Peter N
PN
D000595:Amino Acid Sequence; D000682:Amyloid / Q000737:chemistry* / Q000648:ultrastructure; D002176:Candida albicans / Q000737:chemistry*; D015815:Cell Adhesion Molecules / Q000737:chemistry* / Q000648:ultrastructure; D017124:Conserved Sequence; D019143:Evolution, Molecular; D005656:Fungal Proteins / Q000737:chemistry* / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry; D017510:Protein Folding; D011994:Recombinant Proteins / Q000737:chemistry / Q000648:ultrastructure
C109455:ALA1 protein, Candida albicans; C093538:ALS1 protein, Candida albicans; C113620:ALS3 protein, Candida albicans; D000682:Amyloid; D015815:Cell Adhesion Molecules; D005656:Fungal Proteins; D010455:Peptides; D011994:Recombinant Proteins