Putting enzymes on hold
Table 2. The table shows the absorbance values of the minimum and maximum activity controls. The averages and standard deviations were calculated using the data obtained from three trials, which were then used to determine the Z’ factor. The Max-Min value is the average absorbance of the minimum activity control subtracted from that of the maximum activity control.
A9
D3
D7
E1
G5
G6
G7
I1
I2
Average
0.537
0.512
0.522
0.636
0.512
0.595
0.564
0.562
0.532
Blanks
0.539
0.529
0.519
0.639
0.519
0.609
0.557
0.548
0.568
Adjusted
-0.00167
-0.0173
0.003
-0.003
-0.007
-0.0143
0.0067
0.014
-0.036
% Inhibition
100.5929
106.142
98.93491
101.0651
102.4852
105.0769
97.6213
95.02959
112.7811
Table 3. Table showing the average absorbance values from 3 trials and the absorbance value of 1 blank for each inhibitor (H7 was omitted due to the lack of inhibitor stock). The adjusted values were calculated by subtracting the absorbance value of the blank from the average absorbance value. The percentage inhibition was then calculated using these values and the Max-Min value from the maximum and minimum activity controls. This investigation highlights the potential of Cdc14 inhibitors, particularly D7 and I1, as effective pesticides against Alternaria alternata , while also laying the groundwork for broader research into fungal crop pathogen inhibitors. The substrate specificity assays conducted in this study were essential for detailing the specificity of the Cdc14 active site in A. alternata . Results showed that assays with a catalytic efficiency (Kcat/Km) above 4 nM/s consistently utilized phosphopeptides containing phosphoserine rather than phosphothreonine or phosphotyrosine, suggesting a preference that limits unintended activity. Additionally, assays with a fundamental amino acid around the phosphorylated serine exhibited significantly higher enzymatic activity, underscoring the enzyme’s high specificity and low promiscuity, which could make an inhibitor more selective and effective. Experimental and theoretical results support the use of Cdc14 inhibitors as functional pesticides. Laboratory-based dose-response assays and theoretical docking using the Molecular Operating Environment (MOE) indicated that inhibitors like D7 and I1 could successfully inhibit Cdc14 activity, potentially preventing A. alternata infections, which are particularly detrimental to crops essential to global food security. The designed inhibitor demonstrated a binding affinity of -10.3 kcal/mol, a 70% increase compared to the highest-affinity inhibitor tested. Furthermore, computational models suggest that structural modifications could enable the inhibitor to form disulfide bonds with Cdc14’s cysteine residues, potentially increasing its binding duration and enhancing its competitive inhibition. Future steps will be crucial for validating these findings and ensuring the practical application of the inhibitor. Firstly, the inhibitor must be chemically synthesized and tested on Cdc14 in vitro to confirm its binding efficacy. Toxicity assays will then be necessary to ensure non-toxicity in crops, animals, and
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