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Porins are ideal model systems for channel engineering. OmpG is a robust, monomeric, transmembrane β-barrel without ion selectivity. Here, we present a photocaged diethylaminocoumarin (DEACM) hybrid of OmpG. Blockage of the pore by DEACM is confirmed by reduced conductivity. An optimal effect was obtained when two bulky butyl-substituted coumarin cages were attached on the inside of the pore. Irradiation at 385 nm removed the photocages, leading to a restoration of channel conductivity.

The regioselective cyclometalation of 4-(pyridin-2-yl)phthalimide was exploited for the economical design of organometallic protein kinase inhibitors. 4-(Pyridin-2-yl)phthalimide can be prepared from inexpensive 4-bromophthalimide in just three steps including one Pd-catalyzed Stille cross-coupling. The versatility of this new ligand was demonstrated with the synthesis of ruthenium(II) half-sandwich as well as octahedral ruthenium(II) and iridium(III) complexes. The regioselectivity of the C-H activation in the course of the cyclometalation can be influenced by the reaction conditions and the steric demand of the introduced metal complex fragment. The biological activity of this new class of metalated phthalimides was evaluated by profiling two representative members against a large panel of human protein kinases. A cocrystal structure of one metallo-phthalimide with the protein kinase Pim1 confirmed an ATP-competitive binding with the intended hydrogen bonding between the phthalimide moiety and the hinge region of the ATP-binding site.

The suitability for chemical engineering of the highly symmetrical Mycobacterium tuberculosis dodecin was investigated, its inner cavity providing a large compartment shields introduced compounds from bulk solvent. Hybrids were obtained by S-alkylation of cysteine mutants and characterized by spectroscopic methods, including the crystal structures of wild type and biohybrid dodecins.

Non-ribosomal peptide products often contain modified building blocks or post-assembly line alterations of their peptide scaffolds with some of them being crucial for biological activity. These reactions such as halogenation, hydroxylation or glycosylation are mostly catalyzed by individual enzymes associated with the respective biosynthesis cluster. The versatile nature of these chemical modifications gives rise to a high degree of structural and functional diversity. Recent progress in this area enhances our insight about the mechanisms of these enzymes. Biotechnological applications might include the synthesis of novel, non-ribosomal peptide products or modified amino acid building blocks for pharmaceutical research.

The channel-mediated transport of ions through a membrane is of great importance in biological systems and holds a considerable potential for sensing applications. Ion-channel engineering follows two approaches. The first is the engineering of biological channels with the goal to control existing functionality. Currently, this area benefits from progress in structural information of ion channels, new methods in protein engineering (protein semi-synthesis), and the inclusion of chemical synthesis to obtain hybrid ion channels. The second approach in ion channel engineering is the de novo design. Here, progress emerges from self-assembly concepts to prepare β-barrel and π-barrel pores. This review focuses on contributions published in the year 2007 with inclusion of selected work of the time span 2005–2006.