A1 Refereed original research article in a scientific journal
Anthranilate phosphoribosyltransferase from the hyperthermophilic archaeon Thermococcus kodakarensis shows maximum activity with zinc and forms a unique dimeric structure
Authors: Sumera Perveen, Naeem Rashid, Xiao-Feng Tang, Tadayuki Imanaka, Anastassios C. Papageorgiou
Publisher: WILEY
Publication year: 2017
Journal: FEBS Open Bio
Journal name in source: FEBS OPEN BIO
Journal acronym: FEBS OPEN BIO
Volume: 7
Issue: 8
First page : 1217
Last page: 1230
Number of pages: 14
ISSN: 2211-5463
eISSN: 2211-5463
DOI: https://doi.org/10.1002/2211-5463.12264
Web address : 10.1002/2211-5463.12264
Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/24976027
Anthranilate phosphoribosyltransferase (TrpD) is involved in tryptophan biosynthesis, catalyzing the transfer of a phosphoribosyl group to anthranilate, leading to the generation of phosphoribosyl anthranilate. TrpD belongs to the phosphoribosyltransferase (PRT) superfamily and is the only member of the structural class IV. X-ray structures of TrpD from seven species have been solved to date. Here, functional and structural characterization of a recombinant TrpD from hyperthermophilic archaeon Thermococcus kodakarensis KOD1 (TkTrpD) was carried out. Contrary to previously characterized Mg2+-dependent TrpD enzymes, TkTrpD was found to have a unique divalent cation dependency characterized by maximum activity in the presence of Zn2+ (1580 mu mol.min(-1).mg(-1), the highest reported for any TrpD) followed by Ca2+ (948 mu mol.min(-1).mg(-1)) and Mg2+ (711 mu mol.min(-1).mg(-1)). TkTrpD displayed an unusually low thermostability compared to other previously characterized proteins from T. kodakarensis KOD1. The crystal structure of TkTrpD was determined in free form and in the presence of Zn2+ to 1.9 and 2.4 angstrom resolutions, respectively. TkTrpD structure displayed the typical PRT fold similar to other class IV PRTs, with a small N-terminal -helical domain and a larger C-terminal alpha/beta domain. Electron densities for Zn2+ were identified at the expected zinc-binding motif, DE(217-218), of the enzyme in each subunit of the dimer. Two additional Zn2+ were found at a new dimer interface formed in the presence of Zn2+. A fifth Zn2+ was found bound to Glu118 at crystal lattice contacts and a sixth one was ligated with Glu235. Based on the TkTrpD-Zn2+ structure, it is suggested that the formation of a new dimer may be responsible for the higher enzyme activity of TkTrpD in the presence of Zn2+ ions.
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