Abstract
The Rhodobacter sphaeroides 2.4.1 hisI gene, which encodes a phosphoribosyl-AMP-cyclohydrolase that catalyses the third step in the histidine biosynthetic pathway, has been isolated from a genomic library of this phototrophic bacterium by complementation of an Escherichia coli hisI mutant. Analysis of the nucleotide sequence of the R. sphaeroides hisI gene reveals that it encodes a deduced product of 119 aa with a predicted molecular mass of 13.4 kDa. In contrast to the situation in E. coli, the R. sphaeroides hisI gene encodes a unifunctional protein and it is not linked to the hisE gene. The absence of a single histidine operon like that of E. coli was confirmed by PFGE experiments and complementation analysis of a R. sphaeroides hisI mutant that was constructed by marker exchange. The location of hisI in the R. sphaeroides genome has been determined to be at map co-ordinate 2275 ± 20 of chromosome I.
Original language | English |
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Pages (from-to) | 2071-2078 |
Journal | Microbiology (United Kingdom) |
Volume | 142 |
Issue number | 8 |
DOIs | |
Publication status | Published - 1 Jan 1996 |
Keywords
- Chromosome mapping
- hisI gene
- Histidine biosynthesis
- Rhodobacter sphaeroides