1887

Abstract

The folate operon contains nine genes. The first six genes are involved in the biosynthesis of folic acid and tryptophan and have been characterized previously. The 3-region of the folate operon contains three additional ORFs: , potentially encoding a DNA-binding protein of 68 amino acids, , encoding a protein of 338 amino acids with homology to the Orf1 of the operon, and a putative lysyl-tRNA synthetase gene (). Four transcripts were identified which encode the first two, eight or all nine proteins or only the last protein LysS. The folate operon contains two promoters, one upstream of the first gene and the second preceding . Transcription of the entire folate operon starts 33 bp upstream of the ATG codon of , the first gene of the operon. The -encoded RNA-binding attenuation protein (TRAP) dramatically reduces the steady-state levels of the folate operon transcripts encoding the first eight and all nine proteins, but only has a relatively small effect on the steady-state level of the 2.1 kb transcript encoding the first two genes of the operon, and . In addition, transcription of the folate operon is regulated in a growth-phase-dependent manner. Transcripts were present in very low levels after mid-exponential phase, but were dramatically increased directly after transfer of the cells to fresh medium. These results indicate that transcription of the folate operon is regulated by TRAP and also depends on the growth phase of the culture.

Loading

Article metrics loading...

/content/journal/micro/10.1099/00221287-143-3-979
1997-03-01
2019-10-17
Loading full text...

Full text loading...

http://instance.metastore.ingenta.com/content/journal/micro/10.1099/00221287-143-3-979
Loading
This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error