Our strategy is to replace the Val residue in TEM-1 with a cysteine to produce the V216C mutant and then covalently attach an environment-sensitive fluorescent probe (fluorescein-5-malemide) to Cys (through the formation of a thioether bond) for detecting drug binding at the active site [ 20, 21].
In each complex there are eight enzyme-inhibitor or enzyme-water-inhibitor hydrogen bonds at the active site, three of which are very short.
The newly introduced acylhydrazone and N-phenylbenzamide moieties could form stronger interaction by hydrogen bond at the active site of E. coli PDHc-E1 compared with that of porcine PDHc-E1.
In addition, we showed that the earlier the failure of the H-bond network (especially the H-bonds at the active site), the lower the rupture force.
In addition, the rupture of the H-bonds at the active site in XK263 bound complex occurred later than that in AHA001 bound complex.
The position α in Figure 8 (a) corresponds to the failure of the H-bonds at the active site as well as the failure of the whole H-bond network (see also the snapshot α in Figure 8).
With increasing of the pulling force to a critical value, the H-bonds at the active site (Asp25/Asp25' AHA001) started to rupture, and the average H-bond number decreased to 1, see Figure 3 (a) at 22.25 ns and Figure 4 (a) to (d).
The processing time of exo cellulases is calculated as t process = t move + t hbbreak *nrHb, where t move specifies the time during which the cellulase hydrolyzes the glycosidic bond at the active site and slides along the middle glucan chain by one cellobiose unit.
Previous studies have demonstrated that NO donors N-nitrosoanilines inhibit papain activity via formation of S NO bond formation at the active site while NO donors such as S-nitroso-N-acetyl-penicillamine (SNAP), N-nitrosoaniline derivatives, and S-nitroso-glutathione (GSNO) inhibit the enzyme via S-thiolation by thiyl radicals generated from the S-nitrosothiols.
We assume that the parameters related to the peptide-bond hydrolysis at the active sites are the same for substrate and all resulting products, but the parameters related to peptide transport are substrate dependent.
