Table 1.
Usp45sp silent mutation clone | ΔG of ribosome binding site (AGGAGG) | Secreted nuclease activity (compared to Usp45sp)b | Secreted α-amylase activity (% of Usp45sp)c |
---|---|---|---|
Usp45SM2 | −8.4 | − | 79 ± 5†† |
Usp45SM14 | −8.4 | −− | 83 ± 13 |
Usp45SM11 | −6.1 | −− | 85 ± 3†† |
Usp45sp | −6.1 | * | 100 |
Usp45SM16 | −5.9 | − | 91 ± 12 |
Usp45SM19 | −5.9 | + | 106 ± 16 |
Usp45SM4 | −5.7 | + | 107 ± 6 |
Usp45SM10 | −3.8 | + | 116 ± 5† |
Usp45SM20 | −3.7 | ++ | 103 ± 15 |
Usp45SM5 | −3.7 | + | 113 ± 5† |
Usp45SM8 | −3.3 | + | 92 ± 5 |
Usp45SM15 | −3.3 | + | 100 ± 6 |
Usp45SM9 | −3.3 | + | 114 ± 7 |
Usp45SM7 | −3.2 | + | 105 ± 14 |
Usp45SM6 | −2.5 | ++ | 99 ± 12 |
Usp45SM12 | −1.6 | ++ | 96 ± 12 |
Usp45SM3 | −0.6 | * | 114 ± 3†† |
Nuclease and α-amylase secretion levels are reported for cultures induced with 10 ng/ml nisin for 2 h at mid-log phase. ΔG, mRNA folding energy. Nucleotide sequences are given in Table S4 in the supplemental material.
Data represent levels of nuclease secretion. *, secretion similar to Usp45sp level; −, secretion slightly (<10%) lower than Usp45sp level; −−, secretion much (>10%) lower than Usp45sp level; +, secretion slightly (<10%) higher than Usp45sp level; ++, secretion much (>10%) higher than Usp45sp level.
α-Amylase secretion data represent the means ± standard errors of the means (SEM) of the results of three independent experiments. †, P < 0.05; ††, P < 0.01 (for statistical comparison of α-amylase activities of the respective clone and Usp45sp using one-tailed Student's t test).