In recent years, unprecedented DNA sequencing capacity provided by next generation sequencing (NGS) has revolutionized genomic research. Combining the Illumina sequencing platform and a scFv library designed to confine diversity to both CDR3, >1.9 × 107 sequences have been generated. This approach allowed for in depth analysis of the library’s diversity, provided sequence information on virtually all scFv during selection for binding to two targets and a global view of these enrichment processes. Using the most frequent heavy chain CDR3 sequences, primers were designed to rescue scFv from the third selection round. Identification, based on sequence frequency, retrieved the most potent scFv and valuable candidates that were missed using classical in vitro screening. Thus, by combining NGS with display technologies, laborious and time consuming upfront screening can be by-passed or complemented and valuable insights into the selection process can be obtained to improve library design and understanding of antibody repertoires.

e Mammalian mitochondria may contain up to 1,500 different proteins, and many of them have neither been confidently identified nor characterized. In this study, we demonstrated that C11orf83, which was lacking experimental characterization, is a mitochondrial inner membrane protein facing the intermembrane space. This protein is specifically associated with the bc 1 complex of the electron transport chain and involved in the early stages of its assembly by stabilizing the bc 1 core complex. C11orf83 displays some overlapping functions with Cbp4p, a yeast bc 1 complex assembly factor. Therefore, we suggest that C11orf83, now called UQCC3, is the functional human equivalent of Cbp4p. In addition, C11orf83 depletion in HeLa cells caused abnormal crista morphology, higher sensitivity to apoptosis, a decreased ATP level due to impaired respiration and subtle, but significant, changes in cardiolipin composition. We showed that C11orf83 binds to cardiolipin by its ␣-helices 2 and 3 and is involved in the stabilization of bc 1 complex-containing supercomplexes, especially the III 2 /IV supercomplex. We also demonstrated that the OMA1 metalloprotease cleaves C11orf83 in response to mitochondrial depolarization, suggesting a role in the selection of cells with damaged mitochondria for their subsequent elimination by apoptosis, as previously described for OPA1. Mitochondria are membrane-enclosed organelles composed of several compartments which perform specialized and interconnected functions such as oxidative phosphorylation (OXPHOS), cell death, or carbohydrate and fatty acid metabolisms. OXPHOS, which provides most of the ATP used by the cell, takes place in the inner membrane (IM) and involves five complexes. Redox reactions are carried out by complex I (NADH: ubiquinone oxidoreductase; EC 1.6.5.3), complex II (succinate: ubiquinone oxidoreductase; EC 1.3.5.1), complex III (ubiquinol: ferricytochrome c oxidoreductase; EC 1.10.2.2), and complex IV (cytochrome c oxidoreductase; EC 1.9.3.1). Then, the ATP synthase, complex V (F 1 F 0 ATPase; EC 3.6.3.14), uses the energy released by respiration for ATP generation. The assembly of the OXPHOS complexes requires additional nuclear proteins called assembly factors (1). The physiological importance of these assembly factors is proven by the number of human diseases associated with mutations in genes encoding them (1).Complex III, also called cytochrome bc 1 complex, is a central component of the electron transport chain (ETC). It transfers electrons from coenzyme Q reduced either by complex I through NADH-linked substrates or by complex II through reduced flavin adenine dinucleotide (FADH 2 )-linked substrates to cytochrome c. The mammalian bc 1 complex, which forms as a stable dimer (2), is composed of 11 subunits, among which only MT-CYB is encoded by the mitochondrial genome (3, 4). Most of the work on the bc 1 complex assembly has been performed with Saccharomyces cerevisiae and has shown this to be a multistep process involving several subcomplexes and assembly factors (5...

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