Coiled-coil regions play a role in the function of the Shigella flexneri O-antigen chain length regulator WzzpHS2
Purins, Leanne and Van Den Bosch, Luisa and Richardson, Vanessa and Morona, Renato,, 154, 1104-1116 (2008),
doi = https://doi.org/10.1099/mic.0.2007/014225-0,
publicationName = Microbiology Society,
issn = 1350-0872,
abstract= Regulation of the length of the O-antigen (Oag) chain attached to LPS in Shigella flexneri is important for virulence and is dependent on the inner-membrane protein Wzz. A lack of high-resolution structural data for Wzz has hampered efforts so far to correlate mutations affecting function of Wzz with structure and describe a mechanism for chain length regulation. Here we have used secondary structure prediction to show that the periplasmic domain of the WzzpHS2 protein has three regions of significant coiled-coil (CC) potential, two of which lie within an extended helical region. We describe here the first site-directed mutagenesis study to investigate the role of individual predicted CC regions (CCRs) in Wzz function and oligomerization. We found that CCRs 2 and 3 are necessary for wild-type Oag chain length regulation by WzzpHS2. The in vivo cross-linking profile of mutants affected in the three CCRs was not altered, indicating that individually each CCR is not required for oligomerization. Interestingly, the CCR3 mutation resulted in a temperature-sensitive phenotype and an inhibitory effect on Oag polymerization. Analysis of WzzpHS2 and the mutant constructs in a S. flexneri degP mutant showed that DegP did not affect the function of wild-type WzzpHS2 but its presence influenced the phenotype of the WzzpHS2 CCR3 mutant. Additionally, the phenotype of the WzzpHS2 CCR3 mutant was suppressed by a cis mutation near the putative cytoplasmic C-terminus of WzzpHS2.,
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