9PIK

Structure of the two-pore domain, outwardly rectifying potassium (TOK1) from Candida albicans, overall structure

Summary for 9PIK

• Entry DOI: 10.2210/pdb9pik/pdb
• EMDB information: 71670
• Descriptor: TOK potassium channel, POTASSIUM ION, DODECYL-BETA-D-MALTOSIDE (3 entities in total)
• Functional Keywords: potassium ion channel, metal transport
• Biological source: Candida albicans
• Total number of polymer chains: 2
• Total formula weight: 201126.72

Authors

Durocher, B.,Manville, R.W.,Yan, R.,Yu, Z.,Abbott, G.W.,Miller, A.N. (deposition date: 2025-07-10, release date: 2026-04-29, Last modification date: 2026-05-13)

Primary citation

Durocher, B.,Manville, R.W.,Yan, R.,Yu, Z.,Abbott, G.W.,Miller, A.N.
Molecular architecture of the fungal-specific potassium channel TOK1.
Nat Commun, 2026

PubMed Abstract: In Candida albicans, potassium (K) channels fine-tune ionic balance under stress, contributing to host colonization. Fungal two-pore domain, outwardly rectifying potassium (TOK) channels remain insufficiently characterized despite evidence implicating them in growth and viability. Here, we describe the atomic-resolution structure of a fungal potassium channel, TOK1 from C. albicans (CaTOK), revealing an architecture defined by eight transmembrane helices and a membrane topology distinct from previously characterized K⁺ channel classes. The first four helices form a tetraspanin-like bundle resembling auxiliary subunits of human neuronal ion channels. The pore features an inner helical gating movement analogous to mammalian dimeric K channels, while the K selectivity filter exhibits atypical ion coordination. A cytosolic C-terminal bundle forms an intramolecular network that likely stabilizes CaTOK and may mediate gating. These findings provide a framework for understanding TOK channel function and facilitate future studies of fungal ion homeostasis, pathogenicity, and therapeutic development.

PubMed: 42045187
DOI: 10.1038/s41467-026-72232-y

Experimental method

ELECTRON MICROSCOPY (2.62 Å)