Close linkage of genes encoding glutamine synthetases I and II in Frankia alni CpI1.
AUTOR(ES)
Hosted, T J
RESUMO
Frankia alni CpI1 has two glutamine synthetases (GSs), GSI and GSII. The GSI gene (glnA) was isolated from a cosmid library of F. alni CpI1 DNA by heterologous probing with glnA from Streptomyces coelicolor. The glnA gene was shown to be located upstream of the GSII gene (glnII) by DNA-DNA hybridization. The nucleotide sequences of the 1,422-bp CpI1 glnA gene and of the 449-bp intervening region between glnA and glnII were determined, and the glnA amino acid sequence was deduced. In common with GSIs from other organisms, CpI1 GSI contains five conserved regions near the active site and a conserved tyrosine at the adenylylation site. F. alni CpI1 glnA complemented the glutamine growth requirement of the Escherichia coli glnA deletion strain YMC11 but only when expressed from an E. coli lac promoter. While the functional significance of maintaining two GSs adjacent to one another remains unclear, this arrangement in F. alni provides support for the recently proposed origin of GSI and GSII as resulting from a gene duplication early in the evolution of life.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=204773Documentos Relacionados
- [14C]methylammonium transport by Frankia sp. strain CpI1.
- The actinorhizal root-nodule symbiont Frankia sp. strain CpI1 has two glutamine synthetases
- Enzymes of ammonia assimilation in hyphae and vesicles of Frankia sp. strain CpI1.
- Molecular cloning, sequencing, and expression of the glutamine synthetase II (glnII) gene from the actinomycete root nodule symbiont Frankia sp. strain CpI1.
- Isolation and structure of the lipid envelopes from the nitrogen-fixing vesicles of Frankia sp. strain CpI1.