Structural Biochemistry of a Vibrio cholerae Dinucleotide Cyclase Reveals Cyclase Activity Regulation by Folates

• Published in: Molecular cell Vol. 55; no. 6; pp. 931 - 937
• Main Authors: Zhu, Deyu, Wang, Lijun, Shang, Guijun, Liu, Xue, Zhu, Jing, Lu, Defen, Wang, Lei, Kan, Biao, Zhang, Jing-ren, Xiang, Ye
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 18.09.2014
• Subjects: Amino Acid Sequence; Bacterial Proteins - chemistry; Bacterial Proteins - metabolism; Catalytic Domain; Conserved Sequence; Crystallography, X-Ray; Cyclic AMP - metabolism; Cyclic GMP - metabolism; Folic Acid - analogs & derivatives; Folic Acid - metabolism; Models, Molecular; Molecular Sequence Data; Mutagenesis, Site-Directed; Protein Structure, Tertiary; Vibrio cholerae - chemistry; Vibrio cholerae - enzymology
• ISSN: 1097-2765; 1097-4164
• DOI: 10.1016/j.molcel.2014.08.001

Cyclic dinucleotides are a newly expanded class of second messengers that contribute to the regulation of multiple different pathways in bacterial, eukaryotic, and archaeal cells. The recently identified Vibrio cholerae dinucleotide cyclase (DncV, the gene product of VC0179) can generate three different cyclic dinucleotides and preferentially synthesize a hybrid cyclic-GMP-AMP. Here, we report the crystal structural and functional studies of DncV. We unexpectedly observed a 5-methyltetrahydrofolate diglutamate (5MTHFGLU2) molecule bound in a surface pocket opposite the nucleotide substrate-binding groove of DncV. Subsequent mutagenesis and functional studies showed that the enzymatic activity of DncV is regulated by folate-like molecules, suggesting the existence of a signaling pathway that links folate-like metabolism cofactors to the regulation of cyclic dinucleotide second messenger synthesis. Sequence analysis showed that the residues involved in 5MTHFGLU2 binding are highly conserved in DncV orthologs, implying the presence of this regulation mechanism in a wide variety of bacteria. [Display omitted] •The Vibrio cholerae dinucleotide cyclase (DncV) generates signaling c-dinucleotides•DncV binds folates in a surface pocket opposite its catalytic center•Folate-like metabolism cofactors regulate DncV activity in vitro and in vivo•Cell signaling can be affected by cell metabolism through an enzyme like DncV cGAMP is a newly identified second messenger, which plays important regulatory functions in both prokaryotes and eukaryotes. Bacterial cGAMP is synthesized by DncV. Here Zhu et al. identify a class of unexpected folate-like regulators that bind and regulate DncV, providing a link between bacterial pathogenesis and metabolism.