Stehr Matthias, Hecht Hans Jürgen, Jäger Timo, Flohé Leopold, Singh Mahavir
Department GNA, GBF - Gesellschaft für Biotechnologische Forschung, Mascheroder Weg 1, D-38124 Braunschweig, Germany.
Acta Crystallogr D Biol Crystallogr. 2006 May;62(Pt 5):563-7. doi: 10.1107/S0907444906008249. Epub 2006 Apr 19.
The genome of Mycobacterium tuberculosis encodes several peroxiredoxins (Prxs) thought to be active against organic and inorganic peroxides. The open reading frame Rv1932 encodes a 165-residue thiol peroxidase (Tpx), which belongs to the atypical 2-Cys peroxiredoxin family. The crystal structure of the C60S mutant of M. tuberculosis Tpx (MtTpx) crystallized in space group P3(1)21, with unit-cell parameters a = 106.08, b = 106.08, c = 65.33 A. The structure has been refined to an R value of 17.1% (R(free) = 24.9%) at 2.1 A resolution. MtTpx is structurally homologous to other peroxiredoxins, including the mycobacterial AhpC and AhpE. The inactive MtTpx C60S mutant structure closely resembles the structure of Streptococcus pneumoniae Tpx (SpTpx) and thus represents the reduced enzyme state. The mutated active-site serine is electrostatically linked to Arg130 and hydrogen bonded to Thr57, practically identical to the cysteine in SpTpx. A cocrystallized acetate molecule mimics the position of the substrate and interacts with Ser60, Arg130 and Thr57.
结核分枝杆菌的基因组编码了几种被认为对有机和无机过氧化物具有活性的过氧化物还原酶（Prxs）。开放阅读框Rv1932编码一种165个残基的硫醇过氧化物酶（Tpx），它属于非典型的2-半胱氨酸过氧化物还原酶家族。结核分枝杆菌Tpx（MtTpx）的C60S突变体在空间群P3(1)21中结晶，晶胞参数为a = 106.08，b = 106.08，c = 65.33 Å。该结构在2.1 Å分辨率下已精修至R值为17.1%（R（自由）= 24.9%）。MtTpx在结构上与其他过氧化物还原酶同源，包括分枝杆菌的AhpC和AhpE。无活性的MtTpx C60S突变体结构与肺炎链球菌Tpx（SpTpx）的结构非常相似，因此代表了还原酶状态。突变的活性位点丝氨酸与Arg130静电连接，并与Thr57形成氢键，这与SpTpx中的半胱氨酸几乎相同。一个共结晶的乙酸分子模拟底物的位置，并与Ser60、Arg130和Thr57相互作用。
