Utilization of Cyclodextrins and Its Derivative Particles as Nucleants for Protein Crystallization

Finding new nucleants to promote protein crystallization is an important task, especially for purposes other than structural determination. Here, we investigated cyclodextrins and its derivative particles, as potential nucleants for protein crystallization. β-cyclodextrin (β-CD) and its derivatives (including p-toluenesulfonyl-β-cyclodextrin (PTCD), polymer-β-cyclodextrin (PCD), Mono-(6-(1,6-hexamethylenediamine)-6-deoxy)-β-Cyclodextrin (MHCD) and Mercapto-β-cyclodextrin (MCD)) were used as nucleants. The experimental results confirmed that β-CD and its derivatives showed significantly positive effects, promoting protein crystallization and improving crystal quality. A larger number of protein molecules (including lysozyme, catalase, subtilisin A VIII, concanavalin A VI, α-chymotrypsinogen, proteinase K, cellulase, papain, glucose isomerase, hemoglobin and ribonuclease A XII) attached to the particles usually corresponded to a higher crystallization success rate. More detailed analysis showed that cyclode...