Structure of the MORN4/Myo3a Tail Complex Reveals MORN Repeats as Protein Binding Modules.
Li, J., Liu, H., Raval, M.H., Wan, J., Yengo, C.M., Liu, W., Zhang, M.(2019) Structure 27: 1366
- PubMed: 31279628 
- DOI: https://doi.org/10.1016/j.str.2019.06.004
- Primary Citation of Related Structures:  
6JLE - PubMed Abstract: 
Tandem repeats are basic building blocks for constructing proteins with diverse structures and functions. Compared with extensively studied α-helix-based tandem repeats such as ankyrin, tetratricopeptide, armadillo, and HEAT repeat proteins, relatively little is known about tandem repeat proteins formed by β hairpins. In this study, we discovered that the MORN repeats from MORN4 function as a protein binding module specifically recognizing a tail cargo binding region from Myo3a. The structure of the MORN4/Myo3a complex shows that MORN4 forms an extended single-layered β-sheet structure and uses a U-shaped groove to bind to the Myo3a tail with high affinity and specificity. Sequence and structural analyses further elucidated the unique sequence features for folding and target binding of MORN repeats. Our work establishes that the β-hairpin-based MORN repeats are protein-protein interaction modules.
Organizational Affiliation: 
Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China; Division of Cell, Developmental and Integrative Biology, School of Medicine, South China University of Technology, Guangzhou 510006, China.