Parallel beta-helix proteins required for accurate capsule polysaccharide synthesis and virulence in the yeast Cryptococcus neoformans.

ABSTRACT: The principal capsular polysaccharide of the opportunistic fungal pathogen Cryptococcus neoformans consists of an alpha-1,3-linked mannose backbone decorated with a repeating pattern of glucuronyl and xylosyl side groups. This structure is critical for virulence, yet little is known about how the polymer, called glucuronoxylomannan (GXM), is faithfully synthesized and assembled. We have generated deletions in two genes encoding predicted parallel beta-helix repeat proteins, which we have designated PBX1 and PBX2. Deletion of either gene results in a dry-colony morphology, clumpy cells, and decreased capsule integrity. Two-dimensional nuclear magnetic resonance spectroscopy of purified GXM from the mutants indicated that both the wild-type GXM structure and novel, aberrant linkages were pre

SUBMITTER: Liu OW 

PROVIDER: S-EPMC1865648 | biostudies-literature | 2007 Apr

REPOSITORIES: biostudies-literature