Displays also a weak uracil phosphoribosyltransferase activity which is not physiologically significant (By similarity). Regulates transcriptional attenuation of the pyrimidine nucleotide (pyr) operon by binding in a uridine-dependent manner to specific sites on pyr mRNA. This disrupts an antiterminator hairpin in the RNA and favors formation of a downstream transcription terminator, leading to a reduced expression of downstream genes (By similarity). 175 Pyrimidine operon regulatory protein SaurJH9_1257 pyrR Bifunctional protein pyrR MSERIIMDDAAIQRTVTRIAHEILEYNKGTDNLILLGIKTRGEYLANRIQDKIHQIEQQRIPTGTIDITYFRDDIEHMSSLTTKDAIDIDTDITDKVVIIIDDVLYTGRTVRASLDAILLNARPIKIGLAALVDRGHRELPIRADFVGKNIPTSKEETVSVYLEEMDQRNAVIIK Uracil phosphoribosyltransferase PYRR_STAA9