Unique properties of Zika NS2B-NS3pro complexes as decoded by experiments and MD simulations

Amrita Roy; Liangzhong Lim; Shagun Srivastava; Jianxing Song

The copyright holder for this preprint (which was not peer-reviewed) is the . https://doi.org/10.1101/078113 doi: bioRxiv preprint 9 Interestingly, the kinetic constants were just published for a smaller Zika NS2B-NS3pro which was also linked by the same (Gly)4-Ser-(Gly)4 but had almost all disordered regions removed (25) . It has a Km of 18.3 µM and kcat of 44.6 S -1 respectively. While the kcat values are very similar, the Km value is ~2.4-fold less than our current one. This small difference is likely due to: 1) the difference of substrate as Bz-nKKR-AMC was used in the study (25) ; or/and 2) the presence of more unstructured regions in our construct, 3) or/and the difference of the buffers: our buffer is 50 mM Tris pH 8.5 while the buffer in the publication (25) is only 10 mM Tris pH 8.5. It is well-established that high salt concentrations reduced the activity of the flaviviral proteases (12) (13) (14) (15) (16) (17) (18) . Indeed, we measured the activity of our linked Zika protease in 10 mM Tris pH 8.5, and the catalytic activity is 1.36-time higher.