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Structure of the putative thioesterase protein TTHA1846 from Thermus thermophilus HB8 complexed with coenzyme A and a zinc ion.

Authors :
Hosaka, Toshiaki
Murayama, Kazutaka
Kato-Murayama, Miyuki
Urushibata, Akiko
Akasaka, Ryogo
Terada, Takaho
Shirouzu, Mikako
Kuramitsu, Seiki
Yokoyama, Shigeyuki
Source :
Acta Crystallographica: Section D (Wiley-Blackwell); Aug2009, Vol. 65 Issue 8, p767-776, 10p, 7 Diagrams, 2 Charts
Publication Year :
2009

Abstract

TTHA1846 is a conserved hypothetical protein from Thermus thermophilus HB8 with a molecular mass of 15.1 kDa that belongs to the thioesterase superfamily (Pfam 03061). Here, the 1.9 Å resolution crystal structure of TTHA1846 from T. thermophilus is reported. The crystal structure is a dimer of dimers. Each subunit adopts the so-called hot-dog fold composed of five antiparallel β-strands flanked on one side by a rather long α-helix and shares structural similarity to a number of thioesterases. Unexpectedly, TTHA1846 binds one metal ion and one ligand per subunit. The ligand density was modelled as coenzyme A (CoA). Its structure was confirmed by MALDI-TOF mass spectrometry and electron-density mapping. X-ray absorption fine-structure (XAFS) measurement of the crystal unambiguously characterized the metal ion as zinc. The zinc ion is tetrahedrally coordinated by the side chains of Asp18, His22 and Glu50 and the CoA thiol group. This is the first structural report of the interaction of CoA with a zinc ion. From structural and database analyses, it was speculated that the zinc ion may play an inhibitory role in the enzymatic activity. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
09074449
Volume :
65
Issue :
8
Database :
Complementary Index
Journal :
Acta Crystallographica: Section D (Wiley-Blackwell)
Publication Type :
Academic Journal
Accession number :
44139452
Full Text :
https://doi.org/10.1107/S0907444909015601