11HO

1332D4 Spike KP3.1.1 Complex

Summary for 11HO

• Entry DOI: 10.2210/pdb11ho/pdb
• EMDB information: 75698
• Descriptor: 1332D4 Heavy Chain, 1332D4 Light Chain, SARS-CoV-2 KP3.1.1 variant, ... (5 entities in total)
• Functional Keywords: fab, complex, sars-cov-2, viral protein
• Biological source: Homo sapiens (human); More
• Total number of polymer chains: 5
• Total formula weight: 468533.46

Authors

Kizziah, J.L.,Walter, M.R. (deposition date: 2026-02-24, release date: 2026-08-26, Last modification date: 2026-09-02)

Primary citation

Piepenbrink, M.S.,Ma, Y.,Panjwani, S.,Blake, A.R.,Bell, A.M.,Kizziah, J.L.,Mahmoud, S.H.,Ippolito, G.C.,Erdmann, N.B.,Goepfert, P.A.,Martinez-Sobrido, L.,Kobie, J.J.,Walter, M.R.
Emergence of neutralizing RBD antibodies following Omicron infection with limited activity against ancestral SARS-CoV-2.
Iscience, 29:117166-117166, 2026

PubMed Abstract: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) evolution reduces the efficacy of prophylactic vaccines and monoclonal antibody (mAb) therapies. To evaluate potency and breadth, receptor binding domain (RBD)-targeting neutralizing mAbs were identified from patient B cells using an Omicron KP3.1.1 Spike (S) protein bait. MAbs exhibiting the greatest neutralization potency (1332D4 and 1332E5) and binding breadth (1324A10 and 1316C10) were evaluated in greater detail. Cryo-electron microscopy (Cryo-EM) studies revealed 1332D4 and 1332E5 target RBD residue segments 439-446 and 498-506 of KP3.1.1 S, respectively. 1332E5 is a knob-targeting class-1/4 mAb that exhibits pan-Omicron specificity but does not bind or neutralize ancestral Wuhan-1. Further analysis suggests mAbs generically defined as class 1/4 mAbs may be separated into two classes. Class 1/4 mAbs, like 1332E5, and class 4/1 mAbs that make extensive interactions with the class-4 epitope and limited contacts with the class-1 knob. Despite these differences, the specificity of both mAb classes can be altered by mutations in knob.

PubMed: 42621159
DOI: 10.1016/j.isci.2026.117166

Experimental method

ELECTRON MICROSCOPY (3.26 Å)