9ZR7
Cryo-EM structure of NRAS(Q61K)-BRIL fusion in complex with Fab(BAG2) and Monobody(Mb24)
Summary for 9ZR7
| Entry DOI | 10.2210/pdb9zr7/pdb |
| EMDB information | 74594 |
| Descriptor | GTPase NRas,Soluble cytochrome b562, anti-BRIL Fab, BAG2, heavy chain, anti-BRIL Fab, BAG2, light chain, ... (4 entities in total) |
| Functional Keywords | nras, bril-fusion, oncoprotein, oncoprotein-immune system complex, oncoprotein/immune system |
| Biological source | Homo sapiens (human) More |
| Total number of polymer chains | 3 |
| Total formula weight | 82541.93 |
| Authors | |
| Primary citation | Hu, Z.,Patel, U.R.,Glasser, E.,Koide, A.,Koide, S. Protein Engineering-Enabled Cryo-EM Investigation of Small GTPases. J.Mol.Biol., 438:169860-169860, 2026 Cited by PubMed Abstract: Small GTPases play important roles in cellular signaling. Due to their small sizes (∼21 kDa), structural studies of small GTPases have been predominantly performed using x-ray crystallography in which crystal lattice contacts made it challenging to define unperturbed conformations of the key switch regions. Here, we developed a protein-engineering strategy that enables cryo-EM analysis of small soluble proteins and applied to RAS. We fused the C-terminal α5 helix of the RAS globular domain to a small protein BRIL by forming a continuous helix, which leaves most RAS surfaces exposed to the solvent and unperturbed, followed by the complex formation with an anti-BRIL Fab. This engineered complex with an increased molecular weight, termed "RAS-lollipop", enabled single-particle cryo-EM of RAS. Using this approach, we determined the cryo-EM structure of NRAS, whose structural studies using crystallography have been the least successful among the RAS isoforms. We revealed the conformations of the switch region and α 5 helix that differ from those observed in published crystal structures, and also defined the binding site of an NRAS-specific monobody. We uncovered an unexpected surfactant-like property of this monobody, which reduces orientation biases of particles on cryo-EM grids. Together, this work establishes a platform for visualizing small GTPases and potentially other small proteins with minimal perturbation of their surfaces. PubMed: 42134495DOI: 10.1016/j.jmb.2026.169860 PDB entries with the same primary citation |
| Experimental method | ELECTRON MICROSCOPY (3.28 Å) |
Structure validation
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