title: Core histones of the amitochondriate protist, Giardia lamblia.
abstract: Genes coding for the core histones H2a, H2b, H3, and H4 of Giardia lamblia were sequenced. A conserved organism- and gene-specific element, GRGCGCAGATTTVGG, was found upstream of the coding region in all core histone genes. The derived amino acid sequences of all four histones were similar to their homologs in other eukaryotes, although they were among the most divergent members of this protein family. Comparative protein structure modeling combined with energy evaluation of the resulting models indicated that the G. lamblia core histones individually and together can assume the same three-dimensional structures that were established by X-ray crystallography for Xenopus laevis histones and the nucleosome core particle. Since G. lamblia represents one of the earliest-diverging eukaryotes in many different molecular trees, the structure of its histones is potentially of relevance to understanding histone evolution. The G. lamblia proteins do not represent an intermediate stage between archaeal and eukaryotic histones.
authors.affiliation: Laboratory of Biochemical Parasitology, The Rockefeller University, New York, NY 10021, USA.
authors.forename: G
authors.initials: G
authors.lastname: Wu
authors.forename: A G
authors.initials: AG
authors.lastname: McArthur
authors.forename: A
authors.initials: A
authors.lastname: Fiser
authors.forename: A
authors.initials: A
authors.lastname: Sali
authors.forename: M L
authors.initials: ML
authors.lastname: Sogin
authors.forename: M
authors.initials: M
authors.lastname: Mllerm
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D017124:Conserved Sequence; D016054:DNA, Protozoan / Q000737:chemistry / Q000235:genetics; D005872:Giardia / Q000235:genetics*; D006657:Histones / Q000737:chemistry / Q000235:genetics*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid
chemical_list: D016054:DNA, Protozoan; D006657:Histones