Fig. 2

Location of suppressor mutations that mapped to the inferred CsrA protein within conserved regions and the resulting phenotypes relative to wildtype ES114. The native CsrA protein sequence of ES114 was aligned with the secondary structure consensus (β1-5 and α1) and identified conserved sequences [20, 23] that are region 1, the HA RNA binding GxxG motif, and region 2 (highlighted in blue with yellow text). For each suppressor the deduced native amino acid (column AA) and predicted amino acid substitution, insertion, deletion or elongation is first identified below the consensus in orange text. For native amino acid position, “+” indicates an insertion of the amino acid described, and a “++” signifies frame shift mutations in every case altering more than 10 aa, and all conferring a protein extension (see Table 1). Growth on minimal agar media which was supplemented with glycerol or N-acetylglucosamine is designated by “+” for growth and “-“no growth. Growth yield (OD₆₀₀) is expressed as a percent of wildtype grown overnight in SWT. Blue bars are percent siderophore levels and yellow bars percent luminescence relative to wildtype, where error bars represent 95 % confidence intervals using 5–8 replicates. The names of the strains are color coded by genetic background as described in Table 1