Crystal structure of the single cystathionine β-synthase domain-containing protein CBSX1 from Arabidopsis thaliana

► The structures of full-length and internal-loop deleted CBSX1 were determined. ► The structures of CBSX1 have a unique bend along the side of ∼155°. ► The importance of AMP binding for enhancing Trx activity was confirmed by mutagenesis.