Schwarz Christian K W, Tschapek Britta, Jumpertz Thorsten, Jenewein Stefan, Lecher Justin, Willbold Dieter, Panjikar Santosh, Holland I Barry, Smits Sander H J, Schmitt Lutz
Institute of Biochemistry, Heinrich Heine University Düsseldorf, Universitätsstrasse 1, D-40225 Düsseldorf, Germany.
Acta Crystallogr Sect F Struct Biol Cryst Commun. 2011 May 1;67(Pt 5):630-3. doi: 10.1107/S1744309111010876. Epub 2011 Apr 28.
The ABC transporter haemolysin B (HlyB) from Escherichia coli is part of a type I secretion system that translocates a 110 kDa toxin in one step across both membranes of this Gram-negative bacterium in an ATP-dependent manner. Sequence analysis indicates that HlyB contains a C39 peptidase-like domain at its N-terminus. C39 domains are thiol-dependent peptidases that cleave their substrates after a GG motif. Interestingly, the catalytically invariant cysteine is replaced by a tyrosine in the C39-like domain of HlyB. Here, the overexpression, purification and crystallization of the isolated C39-like domain are described as a first step towards obtaining structural insights into this domain and eventually answering the question concerning the function of a degenerated C39 domain in the ABC transporter HlyB.
来自大肠杆菌的ABC转运蛋白溶血素B（HlyB）是I型分泌系统的一部分，该系统以ATP依赖的方式将一种110 kDa的毒素一步转运穿过这种革兰氏阴性细菌的两层膜。序列分析表明，HlyB在其N端含有一个C39肽酶样结构域。C39结构域是硫醇依赖性肽酶，在GG基序后切割其底物。有趣的是，在HlyB的C39样结构域中，催化不变的半胱氨酸被酪氨酸取代。在此，描述了分离的C39样结构域的过表达、纯化和结晶，这是朝着获得该结构域的结构见解并最终回答关于ABC转运蛋白HlyB中退化的C39结构域功能问题迈出的第一步。
