title: Purification and domain structure of core hnRNP proteins A1 and A2 and their relationship to single-stranded DNA-binding proteins.
abstract: Protein A1 (Mr approximately 32,000), a major glycine-rich protein of heterogeneous nuclear ribonucleoproteins (hnRNP), was purified to near homogeneity under nondenaturing conditions from HeLa cells. Limited proteolysis of the native protein yields a trypsin-resistant N-terminal nucleic acid-binding domain about 195 amino acids long which has a primary structure nearly identical to that of the 195-amino acid-long single-stranded DNA (ssDNA)-binding protein UP1 (Mr 22,162) from calf thymus (Williams, K.R., Stone, K. L., LoPresti, M.B., Merrill, B. M., and Planck, S.R. (1985) Proc. Natl. Acad. Sci. U.S.A. 82, 5666-5670). 45 of the 61 glycine residues of A1 are present in the trypsin-sensitive C-terminal domain of the protein which contains no sequences homologous to UP1. Protein A2, another major glycine-rich core hnRNP protein from HeLa, has a domain structure analogous to A1 and appears to be related to ssDNA-binding proteins UP1-B from calf liver and HDP-1 from mouse myeloma in a way similar to the A1/UP1 relationship. In contrast to ssDNA-binding proteins, A1 binds preferentially to RNA over ssDNA and exhibits no helix-destabilizing activity.
mesh_terms: D000595:Amino Acid Sequence; D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D006367:HeLa Cells / Q000032:analysis; D000076245:Heterogeneous Nuclear Ribonucleoprotein A1; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D006801:Humans; D008970:Molecular Weight; D012261:Ribonucleoproteins / Q000302:isolation & purification*; D013056:Spectrophotometry, Ultraviolet; D014357:Trypsin / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; D000076245:Heterogeneous Nuclear Ribonucleoprotein A1; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B; D034441:Heterogeneous-Nuclear Ribonucleoproteins; C000619657:Hnrnpa1 protein, mouse; D012261:Ribonucleoproteins; C439768:hnRNP A2; C000619656:hnRNPA1 protein, human; D014357:Trypsin