title: The histidine operon of Azospirillum brasilense: organization, nucleotide sequence and functional analysis.
abstract: A 3457-base pair fragment of Azospirillum brasilense DNA which complemented mutations in the hisA and hisF genes of Escherichia coli was sequenced. The sequence analysis revealed the presence of six major contiguous open reading frames (ORF). The comparison of the predicted amino acid sequence of these ORF with those encoded by the eubacterial, archaebacterial and eukaryotic his genes sequenced thus far revealed that four of them have a significant degree of homology with the E. coli hisH, hisA, hisF and the C-terminal domain of the hisI gene products. S1 mapping experiments indicated that the putative transcription start site coincided with the AUG translational initiation codon of the hisBd gene, the first gene of the A. brasilense his operon. Downstream from the last ORF, a sequence was identified which functions as a Rho-independent transcription terminator. Comparison of amino acid sequences, gene order and organization and evolutionary aspects of the A. brasilense his cluster are discussed.
authors.affiliation: Dipartimento di Biologia Animale e Genetica, Università degli Studi, Firenze, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Fani
authors.forename: P
authors.initials: P
authors.lastname: Alifano
authors.forename: G
authors.initials: G
authors.lastname: Allotta
authors.forename: M
authors.initials: M
authors.lastname: Bazzicalupo
authors.forename: M S
authors.initials: MS
authors.lastname: Carlomagno
authors.forename: E
authors.initials: E
authors.lastname: Gallori
authors.forename: F
authors.initials: F
authors.lastname: Rivellini
authors.forename: M
authors.initials: M
authors.lastname: Polsinelli
mesh_terms: D000595:Amino Acid Sequence / Q000235:genetics; D015806:Azospirillum brasilense / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics; D006639:Histidine / Q000235:genetics*; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics; D009876:Operon / Q000235:genetics*; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; D006639:Histidine