title: The human apoptosis-inducing protein AMID is an oxidoreductase with a modified flavin cofactor and DNA binding activity.
abstract: AMID (apoptosis-inducing factor-homologous mitochondrion-associated inducer of death; also known as PRG3 (p53-responsive gene 3)) is a human caspase-independent pro-apoptotic protein with some similarity to apoptosis-inducing factor. AMID was purified from a recombinant bacterial host, enabling biochemical analysis of the protein. AMID is a flavoprotein; possesses NAD(P)H oxidase activity; and catalyzes NAD(P)H-dependent reduction of cytochrome c and other electron acceptors, including molecular oxygen. NADPH binds approximately 10-fold tighter than NADH. AMID binds 6-hydroxy-FAD (a cofactor that accumulates only adventitiously and at low abundance in other flavoprotein enzymes) to form a stoichiometric cofactor.protein complex. AMID has a distinctive electronic spectrum due to the modified flavin. NAD(P)+ binding perturbed the spectrum, enabling determination of K(d) values for these coenzymes. 6-Hydroxy-FAD could be removed from AMID and the apoprotein reconstituted with FAD. FAD was converted to 6-hydroxy-FAD in reconstituted AMID during aerobic turnover with NADPH. AMID is a DNA-binding protein that lacks apparent DNA sequence specificity. Formation of the protein.DNA complex (i) effected a major protein conformational change and (ii) was prevented in the presence of nicotinamide coenzyme. Apo-AMID retains DNA binding activity. Our studies establish a link between coenzyme and DNA binding that likely impacts on the physiological role of AMID in cellular apoptosis.
authors.affiliation: Department of Biochemistry, University of Leicester, Henry Wellcome Building, Lancaster Road, Leicester LE1 9NH, United Kingdom. krm4@le.ac.uk
authors.forename: Ker R
authors.initials: KR
authors.lastname: Marshall
authors.forename: Min
authors.initials: M
authors.lastname: Gong
authors.forename: Leigh
authors.initials: L
authors.lastname: Wodke
authors.forename: John H
authors.initials: JH
authors.lastname: Lamb
authors.forename: Donald J L
authors.initials: DJ
authors.lastname: Jones
authors.forename: Peter B
authors.initials: PB
authors.lastname: Farmer
authors.forename: Nigel S
authors.initials: NS
authors.lastname: Scrutton
authors.forename: Andrew W
authors.initials: AW
authors.lastname: Munro
mesh_terms: D017209:Apoptosis / Q000502:physiology*; D051017:Apoptosis Regulatory Proteins; D003067:Coenzymes / Q000737:chemistry / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005182:Flavin-Adenine Dinucleotide / Q000031:analogs & derivatives / Q000378:metabolism; D005415:Flavins / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009243:NAD / Q000378:metabolism; D009249:NADP / Q000378:metabolism; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding
chemical_list: C462504:ferroptosis suppressor protein 1, human; D051017:Apoptosis Regulatory Proteins; D003067:Coenzymes; D004268:DNA-Binding Proteins; D005415:Flavins; D024101:Mitochondrial Proteins; D009243:NAD; D005182:Flavin-Adenine Dinucleotide; C052277:6-hydroxy-FAD; D009249:NADP; D010088:Oxidoreductases