YchM is the sole E. coli member of the SLC26 superfamily of anion transporters, which are characterized by an N-terminal transport domain and a C-terminal cytosolic STAS (Sulphate Transporter and Anti-Sigma factor antagonist) domain. In a previous study, the STAS domain of YchM co-purified and crystallized with acyl carrier protein (ACP). In this study, analysis of the ACP-STAS interaction using isothermal titration calorimetry (ITC) showed that the 4’phosphopantetheine of ACP and R523 and R527 of the STAS are crucial for binding. The binding constant for the ACP-STAS interaction was found to be 0.7 +/- 0.1 μM. The potential role of YchM for pH regulation and fatty acid degradation studied in vivo indicated that a) YchM does not provide selective advantage for growth in alkaline pH and b) YchM was not essential for cell growth, even when fatty acids were the sole carbon source.

YchM is the sole E. coli member of the SLC26 superfamily of anion transporters, which are characterized by an N-terminal transport domain and a C-terminal cytosolic STAS (Sulphate Transporter and Anti-Sigma factor antagonist) domain. In a previous study, the STAS domain of YchM co-purified and crystallized with acyl carrier protein (ACP). In this study, analysis of the ACP-STAS interaction using isothermal titration calorimetry (ITC) showed that the 4’phosphopantetheine of ACP and R523 and R527 of the STAS are crucial for binding. The binding constant for the ACP-STAS interaction was found to be 0.7 +/- 0.1 μM. The potential role of YchM for pH regulation and fatty acid degradation studied in vivo indicated that a) YchM does not provide selective advantage for growth in alkaline pH and b) YchM was not essential for cell growth, even when fatty acids were the sole carbon source.