The structures of the PDI‐related protein Wind (with a C‐terminal His6 tag) and the mutants Y53S, Y53F and Y55K have been determined and compared with the wild‐type structure with the His6 tag at ...the N‐terminus. All five structures show the same mode of dimerization, showing that this was not an artefact introduced by the nearby N‐terminal His6 tag and suggesting that this dimer may also be the biologically active form. Although the mutants Y53S and Y55K completely abrogate transport of the protein Pipe (which appears to be the primary function of Wind in the cell), only subtle differences can be seen in the putative Pipe‐binding region. The Pipe binding in the active forms appears to involve hydrophobic interactions between aromatic systems, whereas the inactive mutants may be able to bind more strongly with the help of hydrogen bonds, which could disturb the delicate equilibrium required for effective Pipe transport.
The putative transcriptional regulator protein YvoA (BSU35030) from Bacillus subtilis was cloned and heterologously expressed in Escherichia coli. The protein was purified by immobilized ...metal‐affinity chromatography and size‐exclusion chromatography and subsequently crystallized. A complete native data set was collected to 2.50 Å resolution. The crystals belonged to the monoclinic space group C2 and preliminary analysis of the diffraction data indicated the presence of approximately 12 molecules per asymmetric unit.
Aus dem Meer: Gutingimycin (1) aus dem marinen Streptomyceten B8652 ist ein Konjugat aus Guanin und Trioxacarcin A, wie durch NMR‐Untersuchungen und eine Kristallstrukturanalyse gezeigt wurde. Der ...Naturstoff entsteht wahrscheinlich durch einen selektiven Angriff von Trioxacarcin A auf die bakterielle DNA, was zu Strangbrüchen führt und die hohe Cytotoxizität von Trioxacarcin A erklärt.
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