MF7000867 Human FAD-linked augmenter of liver regeneration (ALR) 3o55 X-ray 1.90 Homodimer Homo sapiens 21383138 Banci L, Bertini I, Calderone V, Cefaro C, Ciofi-Baffoni S, Gallo A, Kallergi E, Lionaki E, Pozidis C, Tokatlidis K Proc. Natl. Acad. Sci. U.S.A. 2011 12 108 4811-6 Oxidative protein folding in the mitochondrial intermembrane space requires the transfer of a disulfide bond from MIA40 to the substrate. During this process MIA40 is reduced and regenerated to a functional state through the interaction with the flavin-dependent sulfhydryl oxidase ALR. Here we present the mechanistic basis of ALR-MIA40 interaction at atomic resolution by biochemical and structural analyses of the mitochondrial ALR isoform and its covalent mixed disulfide intermediate with MIA40. This ALR isoform contains a folded FAD-binding domain at the C-terminus and an unstructured, flexible N-terminal domain, weakly and transiently interacting one with the other. A specific region of the N-terminal domain guides the interaction with the MIA40 substrate binding cleft (mimicking the interaction of the substrate itself), without being involved in the import of ALR. The hydrophobicity-driven binding of this region ensures precise protein-protein recognition needed for an efficient electron transfer process. GO:0050660 flavin adenine dinucleotide binding GO:0016971 flavin-dependent sulfhydryl oxidase activity GO:0008083 growth factor activity GO:0015035 protein-disulfide reductase activity GO:0005829 cytosol GO:0005615 extracellular space GO:0005758 mitochondrial intermembrane space GO:0005739 mitochondrion GO:0072717 cellular response to actinomycin D GO:0071222 cellular response to lipopolysaccharide GO:0097237 cellular response to toxic substance GO:0071356 cellular response to tumor necrosis factor GO:0001889 liver development GO:0097421 liver regeneration GO:0043066 negative regulation of apoptotic process GO:0045953 negative regulation of natural killer cell mediated cytotoxicity GO:2000573 positive regulation of DNA biosynthetic process 2 1 Homooligomeric enzymes Homodimeric enzymes All chains according to the most probable oligomerization state stored in PDBe were considered. A FAD-linked sulfhydryl oxidase ALR Homo sapiens P55789 91 205 56% MAAPGERGRFHGGNLFFLPGGARSEMMDDLATDARGRGAGRRDAAASASTPAQAPTSDSPVAEDASRRRPCRACVDFKTWMRTQQKRDTKFREDCPPDREELGRHSWAVLHTLAAYYPDLPTPEQQQDMAQFIHLFSKFYPCEECAEDLRKRLCRNHPDTRTRACFTQWLCHLHNEVNRKLGKPDFDCSKVDERWRDGWKDGSCD 205 secondary structure helix 18 36 secondary structure helix 42 60 secondary structure helix 62 76 secondary structure helix 82 101 secondary structure helix 107 109 secondary structure helix 110 116 pfam PF04777 Erv1 / Alr family 104 196 A-2 FAD-linked sulfhydryl oxidase ALR Homo sapiens P55789 91 205 56% MAAPGERGRFHGGNLFFLPGGARSEMMDDLATDARGRGAGRRDAAASASTPAQAPTSDSPVAEDASRRRPCRACVDFKTWMRTQQKRDTKFREDCPPDREELGRHSWAVLHTLAAYYPDLPTPEQQQDMAQFIHLFSKFYPCEECAEDLRKRLCRNHPDTRTRACFTQWLCHLHNEVNRKLGKPDFDCSKVDERWRDGWKDGSCD 205 pfam PF04777 Erv1 / Alr family 104 196 Insufficient evidence (candidate) The full structure participates in mutual synergistic folding. ERV/ALR sulfhydryl oxidase domain There is no information on the stability/disorder of the monomeric forms of FAD-linked sulfhydryl oxidases. The wild-type protein is a dimer in solution (analytical equilibrium ultracentrifugation) (PMID:19576902). The, large, hydrophobic interface is made up of two longer, nearly antiparallel helices per monomer that mediate helix packing interactions to form the interface. A N/A A-2 N/A MF7000866 MF7000270 MF7000867 MF7000868 MF7000869 MF7000870