Predicting the self-assembly film structure of class II hydrophobin NC2 and estimating its structural characteristics

Hydrophobins are fungal proteins that can mediate water surface tension by forming amphiphilic self-assembly structures in hydrophobic-hydrophilic interfaces. Hydrophobins are known to self-assemble into two forms depending on their class: class I hydrophobins aggregate into a functional amyloid rodlet, while class II hydrophobins aggregate into a regularly patterned monolayer. Owing to its unique properties, hydrophobin has been considered as a biocompatible nanomaterial for various applications and there have been several attempts to engineer hydrophobins to enhance their function. Recently, a chimeric hydrophobin named NChi2 was found to be able to self-assemble into both rodlet and monolayer forms depending on the incubating environment. Although this remarkable feature suggests that NChi2 can function as a versatile bionanomaterial for various applications, only little information about the protein, such as its assembly structure or its characteristics, is provided. To investigate the extraordinary behavior of NChi2, it seems to be a prerequisite to first understand the characteristics of its parent hydrophobins, namely class I EAS and class II NC2. Here, we conducted a preliminary study on predicting the self-assembly structure of class II hydrophobin NC2 and estimating its structural characteristics by employing several computational methods. From the results, we found that NC2 shows stronger surface activity than HFBII, while its assembly structure is weaker than that of HFBII. We hope that this research serves as a foundation to further investigate the structural characteristics of a unique hydrophobin NChi2 in future studies.