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Dimeric crystal structure of HTPA reductase from arabidopsis thaliana
Structural highlights
FunctionDAPB2_ARATH Catalyzes the conversion of 4-hydroxy-tetrahydrodipicolinate (HTPA) to tetrahydrodipicolinate.[1] Publication Abstract from PubMedDihydrodipicolinate reductase (DHDPR) catalyses the second reaction in the diaminopimelate pathway of lysine biosynthesis in bacteria and plants. In contrast to the tetrameric bacterial DHDPR enzymes, we show that DHDPR from Vitis vinifera (grape) and Selaginella moellendorffii are dimeric in solution. In the present study, we have also determined the crystal structures of DHDPR enzymes from the plants Arabidopsis thaliana and S. moellendorffii , which are the first dimeric DHDPR structures. Analysis of these models demonstrates that the dimer forms through the intra-strand interface, and that unique secondary features in the plant enzymes block tetramer assembly. In addition, we have also solved the structure of tetrameric DHDPR from the pathogenic bacteria Neisseria meningitidis Measuring the activity of plant DHDPR enzymes showed that they are much more prone to substrate inhibition than the bacterial enzymes, which appears to be a consequence of increased flexibility of the substrate binding loop and higher affinity for the nucleotide substrate. This higher propensity to substrate inhibition may have consequences for ongoing efforts to increase lysine biosynthesis in plants. Plant DHDPR forms a dimer with unique secondary structure features that preclude higher order assembly.,Watkin SAJ, Keown JR, Richards E, Goldstone DC, Devenish SRA, Pearce FG Biochem J. 2017 Nov 29. pii: BCJ20170709. doi: 10.1042/BCJ20170709. PMID:29187521[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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