7ZL1

PTX3 Pentraxin Domain

Summary for 7ZL1

• Entry DOI: 10.2210/pdb7zl1/pdb
• EMDB information: 14774
• Descriptor: Pentraxin-related protein PTX3, 2-acetamido-2-deoxy-beta-D-glucopyranose (3 entities in total)
• Functional Keywords: ptx3, long pentraxin 3, immune system, innate immunity
• Biological source: Homo sapiens (human)
• Total number of polymer chains: 8
• Total formula weight: 336512.98

Authors

Noone, D.P.,Sharp, T.H. (deposition date: 2022-04-13, release date: 2022-08-03, Last modification date: 2024-10-23)

Primary citation

Noone, D.P.,Dijkstra, D.J.,van der Klugt, T.T.,van Veelen, P.A.,de Ru, A.H.,Hensbergen, P.J.,Trouw, L.A.,Sharp, T.H.
PTX3 structure determination using a hybrid cryoelectron microscopy and AlphaFold approach offers insights into ligand binding and complement activation.
Proc.Natl.Acad.Sci.USA, 119:e2208144119-e2208144119, 2022

PubMed Abstract: Pattern recognition molecules (PRMs) form an important part of innate immunity, where they facilitate the response to infections and damage by triggering processes such as inflammation. The pentraxin family of soluble PRMs comprises long and short pentraxins, with the former containing unique N-terminal regions unrelated to other proteins or each other. No complete high-resolution structural information exists about long pentraxins, unlike the short pentraxins, where there is an abundance of both X-ray and cryoelectron microscopy (cryo-EM)-derived structures. This study presents a high-resolution structure of the prototypical long pentraxin, PTX3. Cryo-EM yielded a 2.5-Å map of the C-terminal pentraxin domains that revealed a radically different quaternary structure compared to other pentraxins, comprising a glycosylated D4 symmetrical octameric complex stabilized by an extensive disulfide network. The cryo-EM map indicated α-helices that extended N terminal of the pentraxin domains that were not fully resolved. AlphaFold was used to predict the remaining N-terminal structure of the octameric PTX3 complex, revealing two long tetrameric coiled coils with two hinge regions, which was validated using classification of cryo-EM two-dimensional averages. The resulting hybrid cryo-EM/AlphaFold structure allowed mapping of ligand binding sites, such as C1q and fibroblast growth factor-2, as well as rationalization of previous biochemical data. Given the relevance of PTX3 in conditions ranging from COVID-19 prognosis, cancer progression, and female infertility, this structure could be used to inform the understanding and rational design of therapies for these disorders and processes.

PubMed: 35939690
DOI: 10.1073/pnas.2208144119

Experimental method

ELECTRON MICROSCOPY (2.5 Å)