Crystal structures of aconitase X enzymes from bacteria and archaea provide insights into the molecular evolution of the aconitase superfamily.
Watanabe, S., Murase, Y., Watanabe, Y., Sakurai, Y., Tajima, K.(2021) Commun Biol 4: 687-687
- PubMed: 34099860 
- DOI: https://doi.org/10.1038/s42003-021-02147-5
- Primary Citation of Related Structures:  
7CNP, 7CNQ, 7CNR, 7CNS, 7D2R - PubMed Abstract: 
Aconitase superfamily members catalyze the homologous isomerization of specific substrates by sequential dehydration and hydration and contain a [4Fe-4S] cluster. However, monomeric and heterodimeric types of function unknown aconitase X (AcnX) have recently been characterized as a cis-3-hydroxy-L-proline dehydratase (AcnX Type-I ) and mevalonate 5-phosphate dehydratase (AcnX Type-II ), respectively. We herein elucidated the crystal structures of AcnX Type-I from Agrobacterium tumefaciens (AtAcnX) and AcnX Type-II from Thermococcus kodakarensis (TkAcnX) without a ligand and in complex with substrates. AtAcnX and TkAcnX contained the [2Fe-2S] and [3Fe-4S] clusters, respectively, conforming to UV and EPR spectroscopy analyses. The binding sites of the [Fe-S] cluster and substrate were clearlydifferent from those that were completely conserved in other aconitase enzymes; however, theoverall structural frameworks and locations of active sites were partially similar to each other.These results provide novel insights into the evolutionary scenario of the aconitase superfamilybased on the recruitment hypothesis.
Organizational Affiliation: 
Department of Bioscience, Graduate School of Agriculture, Ehime University, Matsuyama, Ehime, Japan. irab@agr.ehime-u.ac.jp.