Molecular characterization of mimosinase and cystathionine β-lyase in the Mimosoideae subfamily member Mimosa pudica
Mimosinase degrades the non-protein amino acid mimosine and is thought to have evolved from cystathionine β-lyase (CBL) via gene duplication. However, no study has, to date, compared the molecular characteristics of mimosinase and CBL. We therefore cloned mimosinase and CBL from the Mimosoideae subfamily member Mimosa pudica (Mp) and explored the molecular relationship between mimosinase and CBL for the first time. The recombinant Mp mimosinase degraded both mimosine and cystathionine with a much higher turnover number (kcat) for mimosine compared with cystathionine, and Mp CBL utilized only cystathionine as a substrate. The critical residues implicated in the substrate binding of Arabidopsis thaliana CBL (Tyr-127, Arg-129, Tyr-181, and Arg-440) were highly conserved in both Mp mimosinase and CBL. However, homology modeling and molecular simulation of these enzymes predicted variations in the residues that interact with substrates. A mutation experiment on Mp mimosinase revealed that the disruption of a disulfide bond in the vicinity of the pyridoxal-5′-phosphate domain increased the enzyme’s preference toward cystathionine. Treatment of Mp mimosinase with a disulfide-cleavage agent also decreased mimosinase activity. Furthermore, mutation near the conserved binding residue altered the substrate preference between mimosine and cystathionine. Molecular dynamics simulations of Mp mimosinase suggested a closer coordination of the residues that interact with mimosine at the active site compared with cystathionine, indicating a more compact pocket size for mimosine degradation. This study thus may provide new insights into the molecular diversification of CBL, a C–S lyase, into the C–N lyase mimosinase in the Mimosoideae subfamily.
KeywordsCystathionine β-lyase Homology modeling Mimosinase Mimosine Molecular evolution Molecular dynamics
We thank Dr. Madhugiri Nageswara-Rao and Professor Donovan Baily of the New Mexico State University for providing transcriptomic analysis data for Leucaena leucocephala.
- Chang L (1960) The effect of mimosine on alkaline phosphatase of mouse kidney. J Formos Med Assoc 59:108–114Google Scholar
- Dong Z, Arnold RJ, Yang Y, Park MH, Hrncirova P, Mechref Y, Novotny MV, Zhang JT (2005) Modulation of differentiation-related gene 1 expression by cell cycle blocker mimosine, revealed by proteomic analysis. Mol Cell Proteom 4:993–1001. https://doi.org/10.1074/mcp.M500044-MCP200 CrossRefGoogle Scholar
- Jones R, Blunt C, Holmes J (1976) Enlarged thyroid glands in cattle grazing leucaena pastures. Trop Grassl 10:113–116Google Scholar
- Lin J, Shih Y, Ling K (1962) Studies on the mechanism of toxicity of mimosine (β-(N-[3-hydroxypyridone])-α-aminopropionic acid). 1. Studies of the reactions of mimosine and pyridoxal 5-phosphate using the spectrophotometric method. J Formos Med Assoc 61:997–1003Google Scholar
- Lin J, Kuang T, Ling K (1963) Studies on the mechanism of toxicity of mimosine III. The effect of mimosine on the activity of l-dopa decarboxylase, in vitro. J Formos Med Assoc 62:587–592Google Scholar
- Negi VS, Bingham JP, Li QX, Borthakur D (2013) midD-encoded ‘rhizomimosinase’ from Rhizobium sp. strain TAL1145 is a C–N lyase that catabolizes l-mimosine into 3-hydroxy-4-pyridone, pyruvate and ammonia. Amino Acids 44:1537–1547. https://doi.org/10.1007/s00726-013-1479-z CrossRefPubMedGoogle Scholar
- Qi X, Li MW, Xie M, Liu X, Ni M, Shao G, Song C, Kay-Yuen Yim A, Tao Y, Wong FL, Isobe S, Wong CF, Wong KS, Xu C, Li C, Wang Y, Guan R, Sun F, Fan G, Xiao Z, Zhou F, Phang TH, Liu X, Tong SW, Chan TF, Yiu SM, Tabata S, Wang J, Xu X, Lam HM (2014) Identification of a novel salt tolerance gene in wild soybean by whole-genome sequencing. Nat Commun 5:4340. https://doi.org/10.1038/ncomms5340 CrossRefPubMedPubMedCentralGoogle Scholar
- Qiao S, Murakami K, Zhao Q, Wang B, Seo H, Yamashita H, Li X, Iwamoto T, Ichihara M, Yoshino M (2012) Mimosine-induced apoptosis in C6 glioma cells requires the release of mitochondria-derived reactive oxygen species and p38, JNK activation. Neurochem Res 37:417–427. https://doi.org/10.1007/s11064-011-0628-6 CrossRefPubMedGoogle Scholar
- Vimolmangkang S, Deng X, Owiti A, Meelaph T, Ogutu C, Han Y (2016) Evolutionary origin of the NCSI gene subfamily encoding norcoclaurine synthase is associated with the biosynthesis of benzylisoquinoline alkaloids in plants. Sci Rep 6:26323. https://doi.org/10.1038/srep26323 CrossRefPubMedPubMedCentralGoogle Scholar
- Wu YH, Li XW, Li WQ, Li XH, Li YJ, Hu GY, Liu ZQ, Li D (2016) Fluorofenidone attenuates bleomycin-induced pulmonary fibrosis by inhibiting eukaryotic translation initiation factor 3a (eIF3a) in rats. Eur J Pharmacol 773:42–50. https://doi.org/10.1016/j.ejphar.2016.01.006 CrossRefPubMedGoogle Scholar