Structure of a plant beta-galactosidase C-terminal domain
Rimlumduan, T., Hua, Y.-L., Tanaka, T., Ketudat Cairns, J.R.(2016) Biochim Biophys Acta 1864: 1411-1418
- PubMed: 27451952 
- DOI: https://doi.org/10.1016/j.bbapap.2016.07.005
- Primary Citation of Related Structures:  
5IAZ - PubMed Abstract: 
Most plant β-galactosidases, which belong to glycoside hydrolase family 35, have a C-terminal domain homologous to animal galactose and rhamnose-binding lectins. To investigate the structure and function of this domain, the C-terminal domain of the rice (Oryza sativa L.) β-galactosidase 1 (OsBGal1 Cter) was expressed in Escherichia coli and purified to homogeneity. The free OsBGal1 Cter is monomeric with a native molecular weight of 15kDa. NMR spectroscopy indicated that OsBGal1 Cter comprises five β-strands and one α-helix. The structure of this domain is similar to lectin domains from animals, but loops A and C of OsBGal1 Cter are longer than the corresponding loops from related animal lectins with known structures. In addition, loop A of OsBGal1 Cter was not well defined, suggesting it is flexible. Although OsBGal1 Cter was predicted to be a galactose/rhamnose-binding domain, binding with rhamnose, galactose, glucose, β-1,4-d-galactobiose and raffinose could not be observed in NMR experiments.
Organizational Affiliation: 
School of Biochemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand; Center for Biomolecular Structure, Function and Application, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand.