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Abstract: Coccolithophores are marine phytoplankton that are among the most prolific calcifiers widespread in Earth’s oceans, playing a crucial role in the carbon cycle and in the transport of organic matter to the deep sea. These organisms produce highly complex mineralized scales that are composed of hierarchical assemblies of nano-crystals of calcium carbonate in the form of calcite. Coccolith formation in vivo occurs within compartmentalized mineralisation vesicles derived from the Golgi body, which contain coccolith-associated polysaccharides (‘CAPs’) providing polymorph selection and mediating crystal growth kinetics, and oval organic mineralisation templates, also known as base plates, which promote heterogenous nucleation and further mechanical interlocking of calcite single crystals. Although the function of coccolith base plates in controlling crystal nucleation have been widely studied, their 3D spatial organization and the chemical functional groups present on the crystal nucleation sites, which are two crucial features impacting biomineralization, remain unsolved. Utilising cryo-electron tomography we show that base plates derived from an exemplary coccolithophore Pleurochrysis carterae (Pcar) in their native hydrated state have a complex 3-layered structure. We further demonstrate, for the first time, the edge and rim of the base plate – where the crystals nucleate - are rich in primary amine functionalities that provide binding targets for negatively charged complexes composed of synthetic macromolecules and Ca2+ ions. Our results indicate that electrostatic interactions between the negatively charged biogenic CAPs and the positively charged rim of the base plate are sufficient to mediate the transport of Ca2+ cations to the mineralization sites.

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Abstract: Clathrin-mediated endocytosis (CME) is key to maintaining the transmembrane protein composition of cells’ limiting membranes. During mammalian CME, a reversible phosphorylation event occurs on Thr156 of the μ2 subunit of the main endocytic clathrin adaptor, AP2. We show that this phosphorylation event starts during clathrin-coated pit (CCP) initiation and increases throughout CCP lifetime. μ2Thr156 phosphorylation favors a new, cargo-bound conformation of AP2 and simultaneously creates a binding platform for the endocytic NECAP proteins but without significantly altering AP2’s cargo affinity in vitro. We describe the structural bases of both. NECAP arrival at CCPs parallels that of clathrin and increases with μ2Thr156 phosphorylation. In turn, NECAP recruits drivers of late stages of CCP formation, including SNX9, via a site distinct from where NECAP binds AP2. Disruption of the different modules of this phosphorylation-based temporal regulatory system results in CCP maturation being delayed and/or stalled, hence impairing global rates of CME.

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Abstract: Here, we demonstrate a chemical modification strategy to create biomaterials of the M13 bacteriophage with extraordinary thermal stability, and high compatibility with non-aqueous ionic liquids. The results provide a blueprint for developing soft materials with well-defined architectures that may find broad applicability in the next generation of flexible devices.

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Abstract: As a new class of sustainable carbon material, the term “carbon dots” represents an “umbrella term” as there are many types of materials included. We employ a broad range of techniques to develop understanding on hydrothermally synthesized carbon dots and show how fine tuning the structural features using simple reduction/oxidation reactions can drastically affect their excited state properties. Structural and spectroscopic studies found that photoluminescence originates from direct excitation of localized fluorophores involving oxygen functional groups, while the excitation at graphene‐like features leads to ultrafast phonon‐assisted relaxation and largely quenches the fluorescent quantum yields. This is arguably the first to identify the dynamics of photoluminescence including Stokes’ shift formation, allowing us to fully resolve the relaxation pathways in these carbon dots. The comprehensive investigation sheds light on how understanding the excited state relaxation processes in different carbon structure is crucial for tuning the optical properties for any potential commercial applications.

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Abstract: Porous Organic Cages (POCs) are an emerging class of self-assembling, porous materials with novel properties. They offer a key advantage over other porous materials in permitting facile solution processing and re-assembly. The combination of POCs with metal nanoparticles (NPs) unlocks applications in the area of catalysis. In this context, POCs can function as both the template of ultra-small NPs and a porous, but reprocessable, heterogeneous catalyst support. Here, we demonstrate the synthesis of ultra-small Pd NPs with an imine linked POC known as ‘CC3’, and show that hydrogen gas can be used to form metallic NPs at ∼200 °C without the reduction of the organic cage (and the accompanying, unwanted loss of crystallinity). The resulting materials are characterized using a range of techniques (including powder diffraction, scanning transmission electron microscopy and synchrotron X-ray absorption spectroscopy) and shown to be recrystallizable following dissolution in organic solvent. Their catalytic efficacy is demonstrated using the widely studied carbon monoxide oxidation reaction. This demonstration paves the way for using ultra-small NPs synthesized with POCs as solution-processable, self-assembling porous catalytic materials.