Biomaterial Database

Oxytricha telomere-binding protein: DNA-dependent dimerization of the alpha and beta subunits. 1993

G Fang, and T R Cech

Department of Chemistry and Biochemistry, Howard Hughes Medical Institute, University of Colorado, Boulder 80309-0215.

A telomere-binding protein consisting of 56-kDa (alpha) and 41-kDa (beta) subunits binds specifically to the single-stranded T4G4T4G4 sequence at the termini of macronuclear DNA molecules in Oxytricha nova. The recent availability of separate alpha and beta polypeptides, expressed in Escherichia coli, allows investigation of the assembly of the telomeric complex ("telosome") from its individual components. By mixing wild-type subunits and electrophoretically distinct variants, we verify that the telosome contains one alpha and one beta subunit. By using telomeric DNAs of two lengths, we find that there is one DNA molecule per telosome. The DNA-protein and subunit-subunit interactions were studied by glycerol gradient sedimentation and chemical cross-linking. The formation of alpha-DNA and beta-DNA cross-links in the telomeric complex indicates that both subunits are in proximity to the DNA. When incubated together, both subunits exist predominantly as monomers in the absence of telomeric DNA. Upon binding to DNA, alpha and beta subunits directly interact with each other to form a heterodimer. We suggest that this DNA-dependent dimerization may allow each subunit to carry out distinct functions as a monomer, in addition to its participation in chromosome capping as part of the heterodimer.

UI	MeSH Term	Description	Entries
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D009838	Oligodeoxyribonucleotides	A group of deoxyribonucleotides (up to 12) in which the phosphate residues of each deoxyribonucleotide act as bridges in forming diester linkages between the deoxyribose moieties.	Oligodeoxynucleotide,Oligodeoxyribonucleotide,Oligodeoxynucleotides
D011993	Recombinant Fusion Proteins	Recombinant proteins produced by the GENETIC TRANSLATION of fused genes formed by the combination of NUCLEIC ACID REGULATORY SEQUENCES of one or more genes with the protein coding sequences of one or more genes.	Fusion Proteins, Recombinant,Recombinant Chimeric Protein,Recombinant Fusion Protein,Recombinant Hybrid Protein,Chimeric Proteins, Recombinant,Hybrid Proteins, Recombinant,Recombinant Chimeric Proteins,Recombinant Hybrid Proteins,Chimeric Protein, Recombinant,Fusion Protein, Recombinant,Hybrid Protein, Recombinant,Protein, Recombinant Chimeric,Protein, Recombinant Fusion,Protein, Recombinant Hybrid,Proteins, Recombinant Chimeric,Proteins, Recombinant Fusion,Proteins, Recombinant Hybrid
D004268	DNA-Binding Proteins	Proteins which bind to DNA. The family includes proteins which bind to both double- and single-stranded DNA and also includes specific DNA binding proteins in serum which can be used as markers for malignant diseases.	DNA Helix Destabilizing Proteins,DNA-Binding Protein,Single-Stranded DNA Binding Proteins,DNA Binding Protein,DNA Single-Stranded Binding Protein,SS DNA BP,Single-Stranded DNA-Binding Protein,Binding Protein, DNA,DNA Binding Proteins,DNA Single Stranded Binding Protein,DNA-Binding Protein, Single-Stranded,Protein, DNA-Binding,Single Stranded DNA Binding Protein,Single Stranded DNA Binding Proteins
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001483	Base Sequence	The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.	DNA Sequence,Nucleotide Sequence,RNA Sequence,DNA Sequences,Base Sequences,Nucleotide Sequences,RNA Sequences,Sequence, Base,Sequence, DNA,Sequence, Nucleotide,Sequence, RNA,Sequences, Base,Sequences, DNA,Sequences, Nucleotide,Sequences, RNA
D015800	Protozoan Proteins	Proteins found in any species of protozoan.	Proteins, Protozoan
D016054	DNA, Protozoan	Deoxyribonucleic acid that makes up the genetic material of protozoa.	Protozoan DNA
D016615	Telomere	A terminal section of a chromosome which has a specialized structure and which is involved in chromosomal replication and stability. Its length is believed to be a few hundred base pairs.	Telomeres
D016813	Oxytricha	A genus of ciliate protozoa having a unique cursorial type of locomotion.	Oxytrichas