9NWJ

Apo WT SthK in 3:1 DOPC:POPE nanodiscs

Summary for 9NWJ

• Entry DOI: 10.2210/pdb9nwj/pdb
• Related: 9NWK
• EMDB information: 49883
• Descriptor: Putative transcriptional regulator, Crp/Fnr family, [(2~{R})-1-[2-azanylethoxy(oxidanyl)phosphoryl]oxy-3-hexadecanoyloxy-propan-2-yl] (~{Z})-octadec-9-enoate (2 entities in total)
• Functional Keywords: trans-membrane protein ion channel cyclic nucleotide-gated channel, membrane protein
• Biological source: Spirochaeta thermophila
• Total number of polymer chains: 4
• Total formula weight: 218834.22

Authors

Schmidpeter, P.A.,Newton, A.J. (deposition date: 2025-03-23, release date: 2025-11-12, Last modification date: 2025-12-03)

Primary citation

Newton, A.J.,Latvala, R.D.,Kuforiji, A.E.,Schmidpeter, P.A.M.
Membrane-forming phospholipids allosterically modulate native-state prolyl isomerization in a CNG channel.
Protein Sci., 34:e70383-e70383, 2025

PubMed Abstract: Ion channel activity is intricately linked to the surrounding lipid environment, yet the molecular effects of lipid-mediated regulation remain largely understudied. Here, we show that membrane-forming phospholipids, which are known to modulate the activity of the cyclic nucleotide-gated channel SthK from Spirochaeta thermophila, exhibit effects that extend well beyond the membrane boundary. Using stopped-flow flux assays, we demonstrate that anionic lipids, which are known to promote channel opening, also affect the fast-to-slow activation ratio and the cAMP potency in SthK. Enzymatic catalysis studies confirm that this occurs by altering the cis/trans equilibrium at Pro300 in the apo state. Additionally, cryogenic electron microscopy structures of SthK reveal lipid-dependent conformational changes that propagate from the bundle crossing into the cytosolic domains. All observed effects correlate with the electronegativity of the lipid headgroup, indicating a common underlying mechanism. Our results highlight membrane-forming phospholipids as allosteric regulators of SthK, controlling multiple functional characteristics of the channel.

PubMed: 41263484
DOI: 10.1002/pro.70383

Experimental method

ELECTRON MICROSCOPY (2.69 Å)