Characterization of hydroxymethylpyrimidine phosphate kinase from mesophilic and thermophilic bacteria and structural insights into their differential thermal stability.

Characterization of hydroxymethylpyrimidine phosphate kinase from mesophilic and thermophilic bacteria and structural insights into their differential thermal stability. Arch Biochem Biophys. 2020 May 05;:108389 Authors: Cea PA, Araya G, Vallejos G, Recabarren R, Alzate-Morales J, Babul J, Guixé V, Castro-Fernandez V Abstract The hydroxymethylpyrimidine phosphate kinases (HMPPK) encoded by the thiD gene and involved in the thiamine biosynthesis pathway, can perform two consecutive phosphorylations of 4-amino-5-hydroxymethyl-2-methyl pyrimidine (HMP) and are found in thermophilic and mesophilic bacteria, and only a few characterizations of mesophilic enzymes are available. The presence of another homolog enzyme (pyridoxal kinase) that can only catalyze the first phosphorylation of HMP and encoded by pdxK gene, has hampered a precise annotation in this enzyme family. Here we report the kinetic characterization of two HMPPK with structure available, the mesophilic and thermophilic enzyme from Salmonella typhimurium (StHMPPK) and Thermus thermophilus (TtHMPPK), respectively. Also, given their high structural similarity, we have analyzed the structural determinants of protein thermal stability in these enzymes by molecular dynamics simulation. The results show that pyridoxal kinases (PLK) from gram-positive bacteria (PLK/HMPPK-like enzymes) constitute a phylogenetically separate group from the canonical PLK, but closely related to the HM...
Source: Archives of Biochemistry and Biophysics - Category: Biochemistry Authors: Tags: Arch Biochem Biophys Source Type: research