Abstract
We have previously isolated and characterized a family of auxin amino acid conjugate hydrolases from the legume Medicago truncatula. All characterized members of this family possess a conserved second methionine within the predicted hydrolase domain. We therefore constructed 5′-truncated clones of the hydrolases to investigate whether this methionine could have a potential function. Overall, the hydrolases exhibited altered substrate specificities towards a variety of auxin conjugates tested, with a somewhat broadened substrate range. In vitro hydrolase activity increased over wild-type in several of the shortened proteins, but only for some substrates. The 5′ “head” domain may be serving a regulatory function in the full-length versions of the enzymes or could provide a mechanism to broaden the substrate range in vivo.
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Acknowledgements
This work was supported by a Margaret and Herman Sokol Faculty Fellow Award (#07A). The technical assistance of Silvia Heinze is gratefully acknowledged. We finally wish to thank Lisa Campanella for her generous editorial help and John Smalley for his thoughts on molecular evolution.
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Campanella, J.J., Sigethy, S. & Ludwig-Müller, J. Truncation of Medicago truncatula Auxin Conjugate Hydrolases Alters Substrate Specificity. Plant Mol Biol Rep 29, 745–752 (2011). https://doi.org/10.1007/s11105-010-0266-1
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DOI: https://doi.org/10.1007/s11105-010-0266-1