1VK8

CRYSTAL STRUCTURE OF A PUTATIVE THIAMINE BIOSYNTHESIS/SALVAGE PROTEIN (TM0486) FROM THERMOTOGA MARITIMA AT 1.80 A RESOLUTION

Summary for 1VK8

• Entry DOI: 10.2210/pdb1vk8/pdb
• Descriptor: hypothetical protein TM0486, UNKNOWN LIGAND (3 entities in total)
• Functional Keywords: protein with possible role in cell wall biogenesis, structural genomics, joint center for structural genomics, jcsg, protein structure initiative, psi, biosynthetic protein
• Biological source: Thermotoga maritima
• Total number of polymer chains: 4
• Total formula weight: 49695.10

Authors

Joint Center for Structural Genomics (JCSG) (deposition date: 2004-05-05, release date: 2004-05-18, Last modification date: 2024-11-20)

Primary citation

Dermoun, Z.,Foulon, A.,Miller, M.D.,Harrington, D.J.,Deacon, A.M.,Sebban-Kreuzer, C.,Roche, P.,Lafitte, D.,Bornet, O.,Wilson, I.A.,Dolla, A.
TM0486 from the hyperthermophilic anaerobe Thermotoga maritima is a thiamin-binding protein involved in response of the cell to oxidative conditions.
J.Mol.Biol., 400:463-476, 2010

PubMed Abstract: The COG database was used for a comparative genome analysis with genomes from anaerobic and aerobic microorganisms with the aim of identifying proteins specific to the anaerobic way of life. A total of 33 COGs were identified, five of which correspond to proteins of unknown function. We focused our study on TM0486 from Thermotoga maritima, which belongs to one of these COGs of unknown function, namely COG0011. The crystal structure of the protein was determined at 2 A resolution. The structure adopts a beta alpha beta beta alpha beta ferredoxin-like fold and assembles as a homotetramer. The structure also revealed the presence of a pocket in each monomer that bound an unidentified ligand. NMR and calorimetry revealed that TM0486 specifically bound thiamin with a K(d) of 1.58 microM, but not hydroxymethyl pyrimidine (HMP), which has been implicated as a potential ligand. We demonstrated that the TM0486 gene belongs to the same multicistronic unit as TM0483, TM0484 and TM0485. Although these three genes have been assigned to the transport of HMP, with TM0484 being the periplasmic thiamin/HMP-binding protein and TM0485 and TM0483 the transmembrane and the ATPase components, respectively, our results led us to conclude that this operon encodes an ABC transporter dedicated to thiamin, with TM0486 transporting charged thiamin in the cytoplasm. Given that this transcriptional unit was up-regulated when T. maritima was exposed to oxidative conditions, we propose that, by chelating cytoplasmic thiamin, TM0486 and, by extension, proteins belonging to COG0011 are involved in the response mechanism to stress that could arise during aerobic conditions.

PubMed: 20471400
DOI: 10.1016/j.jmb.2010.05.014

Experimental method

X-RAY DIFFRACTION (1.8 Å)