Cryo-EM reveals the structure and dynamics of a 723-residue malate synthase G.
Ho, M.R., Wu, Y.M., Lu, Y.C., Ko, T.P., Wu, K.P.(2023) J Struct Biol 215: 107958-107958
- PubMed: 36997036
- DOI: https://doi.org/10.1016/j.jsb.2023.107958
- Primary Citation of Related Structures:
7YQM, 7YQN - PubMed Abstract:
Determination of sub-100 kDa (kDa) structures by cryo-electron microscopy (EM) is a longstanding but not straightforward goal. Here, we present a 2.9-Å cryo-EM structure of a 723-amino acid apo-form malate synthase G (MSG) from Escherichia coli. The cryo-EM structure of the 82-kDa MSG exhibits the same global folding as structures resolved by crystallography and nuclear magnetic resonance (NMR) spectroscopy, and the crystal and cryo-EM structures are indistinguishable. Analyses of MSG dynamics reveal consistent conformational flexibilities among the three experimental approaches, most notably that the α/β domain exhibits structural heterogeneity. We observed that sidechains of F453, L454, M629, and E630 residues involved in hosting the cofactor acetyl-CoA and substrate rotate differently between the cryo-EM apo-form and complex crystal structures. Our work demonstrates that the cryo-EM technique can be used to determine structures and conformational heterogeneity of sub-100 kDa biomolecules to a quality as high as that obtained from X-ray crystallography and NMR spectroscopy.
Organizational Affiliation:
Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan.