8UHT | pdb_00008uht

anti-Phosphohistidine Fab hSC44.ck.20.elbow bound to Glu H1

PDB DOI: https://doi.org/10.2210/pdb8UHT/pdb

Classification: IMMUNE SYSTEM
Organism(s): Oryctolagus cuniculus
Expression System: Homo sapiens
Mutation(s): No

Deposited: 2023-10-09 Released: 2025-03-19
Deposition Author(s): Kalagiri, R., Stanfield, R.L., Hunter, T., Wilson, I.A.
Funding Organization(s): National Institutes of Health/National Cancer Institute (NIH/NCI)

Experimental Data Snapshot

Method: X-RAY DIFFRACTION
Resolution: 2.45 Å
R-Value Free:
0.289 (Depositor), 0.288 (DCC)
R-Value Work:
0.244 (Depositor), 0.244 (DCC)
R-Value Observed:
0.246 (Depositor)

Starting Model: experimental
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wwPDB Validation 3D Report Full Report

This is version 1.1 of the entry. See complete history.

Literature

Using phage display for rational engineering of a higher-affinity humanized 3' phosphohistidine-specific antibody.

Martyn, G.D., Kalagiri, R., Veggiani, G., Stanfield, R.L., Choudhuri, I., Sala, M., Meisenhelder, J., Chen, C., Biswas, A., Levy, R.M., Lyumkis, D., Wilson, I.A., Hunter, T., Sidhu, S.S.

(2025) Commun Chem 8: 381-381

PubMed: 41310398 Search on PubMed Search on PubMed Central
DOI: https://doi.org/10.1038/s42004-025-01768-9
Primary Citation Related Structures:
8UHH, 8UHJ, 8UHN, 8UHP, 8UHS, 8UHT, 8UIG, 8UIH, 8UIO, 8UIT, 8UJI

PubMed Abstract:
Histidine phosphorylation is a non-canonical post-translational modification (PTM), with 1-phosphohistidine (1-pHis) and 3-phosphohistidine (3-pHis) isoforms, that is understudied due to a lack of robust reagents, including high-affinity pHis-specific antibodies. Engineering pHis antibodies is challenging due to the labile nature of its phosphoramidate (P-N) bond. We developed a strategy for in vitro engineering of antibodies for the detection of native 3-pHis targets, in which the rabbit SC44-8 anti-3-pTza mAb is humanized into a scaffold (hSC44) that is suitable for phage display. Six unique Fab phage-displayed hSC44 scaffold libraries were screened for antibodies that bound 3-pHis with higher affinity and had specificity for 3-pHis versus 3-pTza. hSC44.20N32F ^L, the best engineered antibody, has ~10-fold higher affinity for 3-pHis than parental hSC44. Eleven new Fab structures, including the first antibody-pHis peptide structures, together with structural and quantum mechanical calculations, provided molecular insights into 3-pHis and 3-pTza discrimination by hSC44.20N32F ^L and the increased affinity obtained through engineering. We demonstrated the utility of these high-affinity 3-pHis-specific antibodies for the recognition of pHis proteins in mammalian cells by immunoblotting and immunofluorescence staining. Our work describes a general method for engineering labile PTM-specific antibodies and provides novel antibodies for investigating the role of 3-pHis in cell biology.