NAD(P)H:quinone-oxidoreductase-1 (NQO1) is a cytosolic enzyme that catalyzes the reduction of various quinones using flavin adenine dinucleotide (FAD) as a cofactor. NQO1 has been also shown to rescue proteins containing intrinsically unstructured domains, such as p53 and p73, from degradation by the 20S proteasome through an unknown mechanism. Here, we studied the nature of interaction between NQO1 and the 20S proteasome. Our study revealed a double negative feedback loop between NQO1 and the 20S proteasome, whereby NQO1 prevents the proteolytic activity of the 20S proteasome and the 20S proteasome degrades the apo form of NQO1. Furthermore, we demonstrate, both in vivo and in vitro, that NQO1 levels are highly dependent on FAD concentration. These observations suggest a link between 20S proteolysis and the metabolic cellular state. More generally, the results may represent a regulatory mechanism by which associated cofactors dictate the stability of proteins, thus coordinating protein levels with the metabolic status.

Functional molecular materials have been obtained by liquid/ vapor-phase epitaxy or layer-by-layer (LbL) assembly with 1) electro-optic responses sufficiently high to build highspeed electro-optical modulators, [1] 2) high-k dielectrics for fabricating organic field effect transistors (OFETs), [2] and 3) ultra-low-b materials to generate molecular wires. [3] Moreover, combining metal-ligand coordination chemistry with stepwise solution-based deposition resulted in the formation of crystalline assemblies, including highly porous metalorganic frameworks (MOFs) on inorganic surfaces. [4] The key for fabricating these and other molecular materials is frequently found in a highly conserved assembly sequence that directs them towards their unique properties and desired function. Similarly, nature dictates the function of enzymes and the genetic information encoded in DNA/RNA by means of the sequence in which the amino acids and nucleotides are arranged. Yet nature is able to create diverse functionalities

Variation's what you need: variation of the assembly sequence in which layers of two isostructural metal complexes are built up leads to molecular materials with electrochemical properties that depend on the assembly sequence. These properties vary from reversible electron transfer to unidirectional current flows and even charge trapping. The sequence-dependent assembly strategy has implications for various disciplines that involve self-assembly.

We demonstrate that molecular gradients on an organic monolayer is formed by preferential binding of ruthenium complexes from solutions also containing equimolar amounts of isostructural osmium complexes. The monolayer consists of a nanometer-thick assembly of 1,3,5-tris(4-pyridylethenyl)benzene (TPEB) covalently attached to a silicon or metal-oxide surface. The molecular gradient of ruthenium and osmium complexes is orthogonal to the surface plane. This gradient propagates throughout the molecular assembly with thicknesses over 30 nm. Using other monolayers consisting of closely related organic molecules or metal complexes results in the formation of molecular assemblies having an homogeneous and equimolar distribution of ruthenium and osmium complexes. Spectroscopic and computational studies revealed that the geometry of the complexes and the electronic properties of their ligands are nearly identical. These subtle differences cause the isostructural osmium and ruthenium complexes to pack differently on modified surfaces as also demonstrated in crystals grown from solution. The different packing behavior, combined with the organic monolayer significantly contributes to the observed differences in chemical composition on the surface.

Herein, we present an approach that integrates molecular logic functions using surface‐confined metallo‐organic assemblies. These assemblies are electrochromic and mimic the behaviour of logic elements. The logic elements are addressed individually by electrochemical methods, and their outputs are simultaneously read‐out optically by UV/Vis absorption spectroscopy. The versatility of our setup is demonstrated by the integration of two multi‐component assemblies; each acting as ternary logic elements. We used also a laminated cell configuration to demonstrate color‐to‐color and color‐to‐transparent transitions. This concept offers a route for the future development of devices with multiple logic states.