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The performance and functionalities of a commercial fifth generation base station are evaluated inside the reverberation chamber at the mmWave frequency range. The base station capability to operates in different propagation environment conditions reproduced by the reverberation chamber is investigated. Throughput, modulation code scheme and beamforming are analyzed for different real life scenarios both in uplink and downlink. Experimental results inform network operators in their evaluation of the base station operation: i) in many scenarios within a laboratory; ii) in the assessment of whether expected benefit justifies the additional costs in an operating actual network.

The study of protein structure and function is a fundamental step for understanding biological systems and for creating a solid ground for future drug development. Despite the development of novel ground-breaking biochemical and bioinformatical tools in the last decades, most proteins found in nature still have unknown assigned function. In this thesis, I present four publications aimed at protein structure and function determination. In these publications we present one method for high-throughput condition screening of membrane proteins for structural studies and three publications that aim at contributing to the understanding of proteins found in the pathogenic bacterium Mycobacterium tuberculosis, the deadliest bacterium worldwide, responsible for over 1 million deaths every year. Membrane proteins are very important targets for drug development. However, the study of membrane proteins is much more complex than fortheir soluble counterpart. In paper I, we developed a high-throughput method for detergent screening of membrane proteins that significantly reduces the time needed to find optimal conditions for structural studies. We developed amethod that allows for the screening of 192 protein-detergent conditions in 3 days. We used a TEV-folding reporter GFP-His tag vector to be able to measure the stability and amount of each sample after detergent solubilization of the cell lysate.In paper II, we characterized the Mycobacterium smegmatis respiratory supercomplex accessory proteins AscF and AscG. AscF and AscG arelocated in close proximity to the D and K proton pathways of Cytochrome c oxidase and might play a regulatory role in the respiratory supercomplex. Wes how how AscF and AscG do not bind nor metals nor nucleotides, but that they are essential for the normal growth of the M. smegmatis. We also show that both proteins are highly conserved in almost whole Mycobacteriales families, including M. tuberculosis. In paper III, we present two novel structures of the

R2-like ligand-binding oxidase (R2lox) is a ferritin-like protein that harbours a heterodinuclear manganese–iron active site. Although R2lox function is yet to be established, the enzyme binds a fatty acid ligand coordinating the metal centre and catalyses the formation of a tyrosine–valine ether cross-link in the protein scaffold upon O2 activation. Here, we characterized the ligands copurified with R2lox by mass spectrometry-based metabolomics. Moreover, we present the crystal structures of two new homologs of R2lox, from Saccharopolyspora erythraea and Sulfolobus acidocaldarius, at 1.38 Å and 2.26 Å resolution, respectively, providing the highest resolution structure for R2lox, as well as new insights into putative mechanisms regulating the function of the enzyme.

NADH (NAD(+)) and its reduced form NADH serve as cofactors for a variety of oxidoreductases that participate in many metabolic pathways. NAD(+) also is used as substrate by ADP-ribosyl transferases and by sirtuins. NAD(+) biosynthesis is one of the most fundamental biochemical pathways in nature, and the ubiquitous NAD(+) synthetase (NadE) catalyzes the final step in this biosynthetic route. Two different classes of NadE have been described to date: dimeric single-domain ammonium-dependent NadE(NH3) and octameric glutamine-dependent NadE(Gln), and the presence of multiple NadE isoforms is relatively common in prokaryotes. Here, we identified a novel dimeric group of NadE(Gln) in bacteria. Substrate preferences and structural analyses suggested that dimeric NadE(Gln) enzymes may constitute evolutionary intermediates between dimeric NadE(NH3) and octameric NadE(Gln). The characterization of additional NadE isoforms in the diazotrophic bacterium Azospirillum brasilense along with the determination of intracellular glutamine levels in response to an ammonium shock led us to propose a model in which these different NadE isoforms became active accordingly to the availability of nitrogen. These data may explain the selective pressures that support the coexistence of multiple isoforms of NadE in some prokaryotes.