%0 Journal Article %A Liu, Qun %A Kriksunov, Irina A. %A Wang, Zhongwu %A Graeff, Richard %A Lee, Hon Cheung %A Hao, Quan %D 2008 %T Hierarchical and Helical Self-Assembly of ADP-Ribosyl Cyclase into Large-Scale Protein Microtubes %U https://acs.figshare.com/articles/journal_contribution/Hierarchical_and_Helical_Self_Assembly_of_ADP_Ribosyl_Cyclase_into_Large_Scale_Protein_Microtubes/2897002 %R 10.1021/jp807990g.s001 %2 https://ndownloader.figshare.com/files/4595143 %K 4.5 Å resolution %K microrods results %K P 61 screw axis %K protein microtube structures %K building blocks %K 5.6 nm %K multifunctional nanobuilding blocks %K scanning electron microscopy %K 35.6 nm %K protein nanochains %X Proteins are macromolecules with characteristic structures and biological functions. It is extremely challenging to obtain protein microtube structures through self-assembly as proteins are very complex and flexible. Here we present a strategy showing how a specific protein, ADP-ribosyl cyclase, helically self-assembles from monomers into hexagonal nanochains and further to highly ordered crystalline microtubes. The structures of protein nanochains and consequently self-assembled superlattice were determined by X-ray crystallography at 4.5 Å resolution and imaged by scanning electron microscopy. The protein initially forms into dimers that have a fixed size of 5.6 nm, and then, helically self-assembles into 35.6 nm long hexagonal nanochains. One such nanochain consists of six dimers (12 monomers) that stack in order by a pseudo P61 screw axis. Seven nanochains produce a series of large-scale assemblies, nanorods, forming the building blocks for microrods. A proposed aging process of microrods results in the formation of hollow microstructures. Synthesis and characterization of large scale self-assembled protein microtubes may pave a new pathway, capable of not only understanding the self-assembly dynamics of biological materials, but also directing design and fabrication of multifunctional nanobuilding blocks with particular applications in biomedical engineering. %I ACS Publications