%0 Journal Article %A Purins, Leanne %A Van Den Bosch, Luisa %A Richardson, Vanessa %A Morona, Renato %T Coiled-coil regions play a role in the function of the Shigella flexneri O-antigen chain length regulator WzzpHS2 %D 2008 %J Microbiology, %V 154 %N 4 %P 1104-1116 %@ 1465-2080 %R https://doi.org/10.1099/mic.0.2007/014225-0 %K IM, inner membrane %K PCP, polysaccharide copolymerase %K Oag, O-antigen %K CCR, coiled-coil region %K RU, repeat unit %K VL-type, very long type %K CC, coiled-coil %K S-type, short-type %K TM, transmembrane %K ts, temperature sensitive %I Microbiology Society, %X 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. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/mic.0.2007/014225-0