Biochem. J. (2007) 404
(365–372) (Printed in Great Britain)
Chemical structure of the cell-wall mannan of Candida albicans serotype A and its difference in yeast and hyphal forms
Nobuyuki SHIBATA*1, Akifumi SUZUKI†, Hidemitsu KOBAYASHI‡ and Yoshio OKAWA*
*Department of Infection and Host Defense, Tohoku Pharmaceutical University, Sendai, Miyagi 981-8558, Japan, †Tohoku University Hospital, Sendai, Miyagi 980-8574, Japan, and ‡Department of Pharmacy, Faculty of Pharmaceutical Sciences, Nagasaki International University, Sasebo, Nagasaki 859-3298, Japan
The structure of the cell-wall mannan from the J-1012 (serotype A) strain of the polymorphic yeast Candida albicans was determined by acetolysis under mild conditions followed by HPLC and sequential NMR experiments. The serotype A mannan contained b-1,2-linked mannose residues attached to a-1,3-linked mannose residues and a-1,6-linked branching mannose residues. Using a b-1,2-mannosyltransferase, we synthesized a three-b-1,2-linkage-containing mannoheptaose and used it as a reference oligosaccharide for 1H-NMR assignment. On the basis of the results obtained, we derived an additivity rule for the 1H-NMR chemical shifts of the b-1,2-linked mannose residues. The morphological transformation of Candida cells from the yeast form to the hyphal form induced a significant decrease in the phosphodiesterified acid-labile b-1,2-linked manno-oligosaccharides, whereas the amount of acid-stable b-1,2 linkage-containing side chains did not change. These results suggest that the Candida mannan in candidiasis patients contains b-1,2-linked mannose residues and that they behave as a target of the immune system.
Key words: Candida albicans, cell-wall mannan, mannosyltransferase, nuclear-magnetic-resonance spectrum (NMR spectrum), yeast hyphal form, b-1,2-linked mannose.
Abbreviations used: 2D, two-dimensional; ROESY, rotating frame Overhauser enhancement spectroscopy.
1To whom correspondence should be addressed (email nshibata@tohoku-pharm.ac.jp).
Received 15 January 2007/27 February 2007; accepted 1 March 2007
Published as BJ Immediate Publication 1 March 2007, doi:10.1042/BJ20070081
© The Authors Journal compilation © 2007 Biochemical Society
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