title: Fanconi anemia complementation group A (FANCA) protein has intrinsic affinity for nucleic acids with preference for single-stranded forms.
abstract: The Fanconi anemia complementation group A (FANCA) gene is one of 15 disease-causing genes and has been found to be mutated in ∼60% of Fanconi anemia patients. Using purified protein, we report that human FANCA has intrinsic affinity for nucleic acids. FANCA binds to both single-stranded (ssDNA) and double-stranded (dsDNA) DNAs; however, its affinity for ssDNA is significantly higher than for dsDNA in an electrophoretic mobility shift assay. FANCA also binds to RNA with an intriguingly higher affinity than its DNA counterpart. FANCA requires a certain length of nucleic acids for optimal binding. Using DNA and RNA ladders, we determined that the minimum number of nucleotides required for FANCA recognition is ∼30 for both DNA and RNA. By testing the affinity between FANCA and a variety of DNA structures, we found that a 5'-flap or 5'-tail on DNA facilitates its interaction with FANCA. A patient-derived FANCA truncation mutant (Q772X) has diminished affinity for both DNA and RNA. In contrast, the complementing C-terminal fragment of Q772X, C772-1455, retains the differentiated nucleic acid-binding activity (RNA > ssDNA > dsDNA), indicating that the nucleic acid-binding domain of FANCA is located primarily at its C terminus, where most disease-causing mutations are found.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, Florida 33136, USA.
authors.forename: Fenghua
authors.initials: F
authors.lastname: Yuan
authors.forename: Liangyue
authors.initials: L
authors.lastname: Qian
authors.forename: Xinliang
authors.initials: X
authors.lastname: Zhao
authors.forename: Jesse Y
authors.initials: JY
authors.lastname: Liu
authors.forename: Limin
authors.initials: L
authors.lastname: Song
authors.forename: Gennaro
authors.initials: G
authors.lastname: D'Urso
authors.forename: Chaitanya
authors.initials: C
authors.lastname: Jain
authors.forename: Yanbin
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D019943:Amino Acid Substitution; D004277:DNA, Single-Stranded / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D005199:Fanconi Anemia / Q000235:genetics / Q000378:metabolism; D052217:Fanconi Anemia Complementation Group A Protein / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D020125:Mutation, Missense; D010449:Peptide Mapping; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012313:RNA / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; C498471:FANCA protein, human; D052217:Fanconi Anemia Complementation Group A Protein; D016601:RNA-Binding Proteins; D011994:Recombinant Proteins; D012313:RNA