In this pre-cleavage structure, the N terminus of the CANTD is unfolded, suggesting that the N-terminal β-hairpin of the mature CA protein (Fig. 2) forms after MA CA cleavage.
From the post-cleavage structure, H956 makes many hydrogen bond contacts compared to C997, the loss of which would explain the loss of activity and fold on mutation.
A total of five tryptophan residues are located in the NS2-3 precursor, three in the NS2 cytoplasmic domain and two in the NS3 protease domain; as shown in Fig. 8, it appears that in the folded post-cleavage structures of NS2 and NS3 [20,24], the tryptophan residues are in both buried and solvent-exposed regions.
The post-cleavage crystal structure of NS2 suggests that dimerisation is required for the activity of the autoprotease [20].
Auto-cleavage by NS2-3 is a key step in the viral life cycle and is therefore a potential drug target, but little is known regarding its pre-cleavage protein structure, molecular mechanism and the regulation of this process.
Heparanase, an endoglucuronidase responsible for heparan sulfate cleavage, regulates the structure and function of heparan sulfate proteoglycans, leading to disassembly of the extracellular matrix.
Pronase also yields similar digestion patterns in these variants, but further proteolysis was also observed, suggesting that the primary cleavage relaxes GFP structure and reveals previously inaccessible sites.
In ToF-SIMS spectra obtained at 500 °C, the characteristic ions for graphene, which are related to cleavage of ring structure, include Cx+ (x = 1, 2, 3…), CxH+ and CxH2+ as well as Cx− and CxH−.
The unfavorable molecule (11) can further react with hydroxyl radical anion generated in the reaction mixture through the electrochemically driven homolytic cleavage and create structure (12).
