Download MendeleyStructural Basis for Specificity and Flexibility in a Plant 4-Coumarate:CoA Ligase.
Li, Z., Nair, S.K.(2015) Structure 23: 2032-2042
- PubMed: 26412334
- DOI: https://doi.org/10.1016/j.str.2015.08.012
- Primary Citation of Related Structures:
5BSM, 5BSR, 5BST, 5BSU, 5BSV, 5BSW - PubMed Abstract:
Plant 4-coumarate:CoA ligase (4CL) serves as a central catalyst in the phenylpropanoid pathway that provides precursors for numerous metabolites and regulates carbon flow. Here, we present several high-resolution crystal structures of Nicotiana tabacum 4CL isoform 2 (Nt4CL2) in complex with Mg(2+) and ATP, with AMP and coenzyme A (CoA), and with three different hydroxycinnamate-AMP intermediates: 4-coumaroyl-AMP, caffeoyl-AMP, and feruloyl-AMP. The Nt4CL2-Mg(2+)-ATP structure is captured in the adenylate-forming conformation, whereas the other structures are in the thioester-forming conformation. These structures represent a rare example of an ANL enzyme visualized in both conformations, and also reveal the binding determinants for both CoA and the hydroxycinnamate substrate. Kinetic studies of structure-based variants were used to identify residues crucial to catalysis, ATP binding, and hydroxycinnamate specificity. Lastly, we characterize a deletion mutant of Nt4CL2 that possesses the unusual sinapinate-utilizing activity. These studies establish a molecular framework for the engineering of this versatile biocatalyst.
Organizational Affiliation:
Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
