Structural insights into curdlan degradation via a glycoside hydrolase containing a disruptive carbohydrate-binding module

Table 2 Kinetic parameters of CBM6E WT and variants targeting potential ancillary binding sites for triple-helical curdlan, as identified by molecular docking, using curdlan high-set gels as substrate

Protein name	K_0.5^a (mg/mL)	k_cat^a (s⁻¹)	Hill coefficient (h)^a	k_cat/K_0.5^a (s⁻¹ mg⁻¹ mL)
WT	7.6 ± 0.3	0.7 ± 0.05	2.5 ± 0.6	0.09
Y98A	7.7 ± 0.4	0.6 ± 0.03	1.9 ± 0.3	0.08
Q108A	8.5 ± 0.7	0.6 ± 0.05	1.6 ± 0.2	0.07
E173A	7.9 ± 0.5	0.6 ± 0.05	2.2 ± 0.5	0.08

	K_m^b (mg/mL)	k_cat^b (s⁻¹)	/^b	k_cat/K_m^b (s⁻¹ mg⁻¹ mL)
WT	16.7 ± 3.1	1.3 ± 0.13	/	0.08
S315A	20.4 ± 1.6	0.9 ± 0.05	/	0.04
E316A	18.2 ± 2.0	0.8 ± 0.05	/	0.04
T376A	24.1 ± 1.4	0.9 ± 0.03	/	0.04
S315A/T376A	N/A^c, > 25	0.7 ± 0.09	/	N/A^c
E316A/T376A	N/A^c, > 25	0.8 ± 0.1	/	N/A^c

^aThe data from the WT, Y98A, Q108A, and E173A variants were fitted well using the Hill model, as opposed to the Michaelis–Menten model
^bThe data from the S315A, E316A, T376A, S315A/T376A, and E316A/T376A mutants did not converge when using the Hill model; hence, a simple Michaelis–Menten model was employed instead. The WT data were re-fitted for comparison using the Michaelis–Menten model
^cK_m values for the combined variants were not calculated due to insufficient saturation levels for accurate extrapolation

ISSN: 2731-3654