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| Title | Disulfide-stabilized diabodies enable near-atomic cryo-EM imaging of small proteins: A case study of the bacterial Na/citrate symporter CitS. |
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| Journal, issue, pages | Structure, Vol. 33, Issue 6, Page 1088-11100.e3, Year 2025 |
| Publish date | Jun 5, 2025 |
Authors | Subin Kim / Ji Won Kim / Jun Gyou Park / Sang Soo Lee / Seung Hun Choi / Jie-Oh Lee / Mi Sun Jin / ![]() |
| PubMed Abstract | Diabodies are engineered antibody fragments with two antigen-binding Fv domains. Previously, we demonstrated that they are often highly flexible but can be rigidified by introducing a disulfide bond ...Diabodies are engineered antibody fragments with two antigen-binding Fv domains. Previously, we demonstrated that they are often highly flexible but can be rigidified by introducing a disulfide bond at the Fv interface. In this study, we explored the potential of disulfide-bridged, bispecific diabodies for near-atomic cryoelectron microscopy (cryo-EM) imaging of small proteins because they can predictably link target proteins to "structural marker" proteins. As a case study, we used the bacterial citrate transporter CitS as the target protein, and the horseshoe-shaped ectodomain of human Toll-like receptor 3 (TLR3) as the marker. We show that diabodies containing one or two disulfide bonds enabled the 3D reconstruction of CitS at resolutions of 3.3 Å and 3.1 Å, respectively. This resolution surpassed previous crystallographic results and allowed us to visualize the high-resolution structural features of the transporter. Our work expands the application of diabodies in structural biology to address a key limitation in the field. |
External links | Structure / PubMed:40169000 |
| Methods | EM (single particle) |
| Resolution | 2.9 - 3.8 Å |
| Structure data | EMDB-63355, PDB-9lsh: EMDB-63356, PDB-9lsi: EMDB-63357, PDB-9lsj: EMDB-63358, PDB-9lsk: |
| Chemicals | ![]() ChemComp-CIT: ![]() ChemComp-PLM: ![]() ChemComp-NAG: |
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Keywords | STRUCTURAL PROTEIN/IMMUNE SYSTEM / Disulfide-bridged diabody / cryo-electron microscopy (cryo-EM) / small protein imaging / structural marker / antibody engineering / protein nanotechnology / STRUCTURAL PROTEIN / STRUCTURAL PROTEIN-IMMUNE SYSTEM complex / MEMBRANE PROTEIN |
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klebsiella pneumoniae (bacteria)
homo sapiens (human)
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