Adaptation of an enzyme to regulatory function: structure of Bacillus subtilis PyrR, a pyr RNA-binding attenuation protein and uracil phosphoribosyltransferase.Tomchick, D.R., Turner, R.J., Switzer, R.L., Smith, J.L.
(1998) Structure 6: 337-350
- PubMed: 9551555
- DOI: https://doi.org/10.1016/s0969-2126(98)00036-7
- Primary Citation of Related Structures:
- PubMed Abstract:
The expression of pyrimidine nucleotide biosynthetic (pyr) genes in Bacillus subtilis is regulated by transcriptional attenuation. The PyrR attenuation protein binds to specific sites in pyr mRNA, allowing the formation of downstream terminator structures. UMP and 5-phosphoribosyl-1-pyrophosphate (PRPP), a nucleotide metabolite, are co-regulators with PyrR. The smallest RNA shown to bind tightly to PyrR is a 28-30 nucleotide stem-loop that contains a purine-rich bulge and a putative-GNRA tetraloop. PyrR is also a uracil phosphoribosyltransferase (UPRTase), although the relationship between enzymatic activity and RNA recognition is unclear, and the UPRTase activity of PyrR is not physiologically significant in B. subtilis. Elucidating the role of PyrR structural motifs in UMP-dependent RNA binding is an important step towards understanding the mechanism of pyr transcriptional attenuation.
Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907, USA.