9UTU

Structure of Fks1 in complex with YMR295C

Summary for 9UTU

• Entry DOI: 10.2210/pdb9utu/pdb
• EMDB information: 37602 64501
• Descriptor: 1,3-beta-glucan synthase component FKS1, YMR295C isoform 1, MAGNESIUM ION (3 entities in total)
• Functional Keywords: membrane protein
• Biological source: Saccharomyces cerevisiae (brewer's yeast); More
• Total number of polymer chains: 2
• Total formula weight: 237310.14

Authors

Li, J.L.,Zhu, A.Q.,Wang, X.,Yan, C.Y.,Deng, D. (deposition date: 2025-05-05, release date: 2025-12-17, Last modification date: 2026-01-28)

Primary citation

Li, J.,Li, J.,Zhu, A.,Dai, X.,Liu, J.,Liu, H.,Xia, Z.,Dong, Y.,Qian, W.,Dai, L.,Guo, L.,Yan, C.,Deng, D.,Luo, Y.,Wang, X.
Structural-guided identification of two modulators of beta-1,3-glucan synthase FKS1.
Nat Commun, 17:591-591, 2025

PubMed Abstract: FKS1 is a β-1,3-glucan synthase critical for fungal cell wall formation and a target for antifungal drugs such as echinocandin and ibrexafungerp. However, the mechanisms regulating FKS1 activity remain largely unknown. Here, we reveal that transfer RNA (tRNA) acts as an endogenous inhibitor, whereas GSR1 functions as a stabilizer of FKS1. The cryo-EM structure of FKS1 adopts a tRNA-mediated homodimer configuration, representing a quiescent state of β-1,3-glucan synthase. Unexpectedly, the copurified endogenous tRNA is identified as a potent inhibitor that suppresses FKS1 activity. Moreover, high-resolution cryo-EM density analysis enable the identification of GSR1 as an additional binding partner of FKS1. Mutagenesis experiments confirm the interaction between FKS1 and GSR1. Evolutionarily conserved GSR1 is found to increase the stability of FKS1 in β-1,3-glucan biosynthesis. Collectively, our findings identify both tRNA and GSR1 as intrinsic modulators of β-1,3-glucan biosynthesis, thereby providing opportunities for the further development of FKS1-targeted antifungal drugs.

PubMed: 41354657
DOI: 10.1038/s41467-025-67293-4

Experimental method

ELECTRON MICROSCOPY (2.72 Å)