Although regulatory small RNAs have been reported in photosynthetic cyanobacteria, the lack of clear RNA chaperones involved in their regulation poses a conundrum. Here, we analyzed the full complement of cellular RNAs and proteins using gradient profiling by sequencing (Grad-seq) in Synechocystis 6803. Complexes with overlapping subunits such as the CpcG1-type versus the CpcL-type phycobilisomes or the PsaK1 versus PsaK2 photosystem I pre(complexes) could be distinguished, supporting the high quality of this approach. Clustering of the in-gradient distribution profiles followed by several additional criteria yielded a short list of potential RNA chaperones that include an YlxR homolog and a cyanobacterial homolog of the KhpA/B complex. The data suggest previously undetected complexes between accessory proteins and CRISPR-Cas systems, such as a Csx1-Csm6 ribonucleolytic defense complex. Moreover, the exclusive association of either RpoZ or 6S RNA with the core RNA polymerase complex and the existence of a reservoir of inactive sigma–antisigma complexes is suggested. The Synechocystis Grad-seq resource is available online at https://sunshine.biologie.uni-freiburg.de/GradSeqExplorer/ providing a comprehensive resource for the functional assignment of RNA–protein complexes and multisubunit protein complexes in a photosynthetic organism.

The cis/trans isomerization of cis‐PA upon cathodic reduction can be detected voltammetrically. The analysis of the redox data reveals that the trans‐form is thermodynamically more favourable in the charged than in the neutral state. Cyclic voltammetry also reflects geometric relaxation processes which occur in conjugated materials such as PPy or PTh during charging and discharging. The results are in good agreement with quantummechanical predictions based on the bipolaron model. Additional spectroelectrochemical studies unambiguously show that the charging process in the whole accessible potential range is faradaic.

Diffusion I Electrochemistry I Quartz Microbalance I Transport PropertiesOxidation of pyrrole yields a charged polymer film with incorporated anions. During the following reduction electroneutrality can be maintained by expulsion of these anions or by incorporation of cations. The contribution of both processes to the overall charge transport is found to depend strongly on the formation potential during polymerization. The redox process of polypyrrole formed at + 1 .O V vs. Agl AgCl is accompanied by a change in mass, which can be interpreted by a simultaneous transport of anions and cations. A lower formation potential leads to a separation of the charge transport in an either anion or cation dominated region. These differences are related to a cathodically shifted first reduction which occurs if a low formation potential was used. The charge transfer at the electrode and at the polymersolution interface is illustrated by a physical model. It consists of an (E)"-C-(E),,, mechanism for the redox behavior of the polymer and a first-order reaction for incorporation and expulsion of ions. Computed voltammograms and mass curves are presented for different situations and compared to experimental conditions.

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