title: CC1, a novel crenarchaeal DNA binding protein.
abstract: The genomes of the related crenarchaea Pyrobaculum aerophilum and Thermoproteus tenax lack any obvious gene encoding a single-stranded DNA binding protein (SSB). SSBs are essential for DNA replication, recombination, and repair and are found in all other genomes across the three domains of life. These two archaeal genomes also have only one identifiable gene encoding a chromatin protein (the Alba protein), while most other archaea have at least two different abundant chromatin proteins. We performed a biochemical screen for novel nucleic acid binding proteins present in cell extracts of T. tenax. An assay for proteins capable of binding to a single-stranded DNA oligonucleotide resulted in identification of three proteins. The first protein, Alba, has been shown previously to bind single-stranded DNA as well as duplex DNA. The two other proteins, which we designated CC1 (for crenarchaeal chromatin protein 1), are very closely related to one another, and homologs are restricted to the P. aerophilum and Aeropyrum pernix genomes. CC1 is a 6-kDa, monomeric, basic protein that is expressed at a high level in T. tenax. This protein binds single- and double-stranded DNAs with similar affinities. These properties are consistent with a role for CC1 as a crenarchaeal chromatin protein.
authors.affiliation: Centre for Biomolecular Sciences, University of St. Andrews, St. Andrews, Fife KY16 9ST, UK.
authors.forename: Xiao
authors.initials: X
authors.lastname: Luo
authors.forename: Uli
authors.initials: U
authors.lastname: Schwarz-Linek
authors.forename: Catherine H
authors.initials: CH
authors.lastname: Botting
authors.forename: Reinhard
authors.initials: R
authors.lastname: Hensel
authors.forename: Bettina
authors.initials: B
authors.lastname: Siebers
authors.forename: Malcolm F
authors.initials: MF
authors.lastname: White
mesh_terms: D000595:Amino Acid Sequence; D019843:Archaeal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002942:Circular Dichroism; D019615:Crenarchaeota / Q000235:genetics / Q000378:metabolism*; D004277:DNA, Single-Stranded / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D024202:Electrophoretic Mobility Shift Assay; D020745:Genome, Archaeal; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D011485:Protein Binding; D041543:Pyrobaculum / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D021241:Spectrometry, Mass, Electrospray Ionization; D041542:Thermoproteus / Q000235:genetics / Q000378:metabolism
chemical_list: D019843:Archaeal Proteins; D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins