The δ subunit and NTPase HelD institute a two-pronged mechanism for RNA polymerase recycling

Cellular RNA polymerases RNAPs can become trapped on DNA or RNA, threatening genome stability and limiting free enzyme pools, but how RNAP recycling into active states is achieved remains elusive. In Bacillus subtilis, the RNAP amp; 948; subunit and NTPase HelD have been implicated in RNAP recycling. We structurally analyzed Bacillus subtilis RNAP amp; 948; HelD complexes. HelD has two long arms a Gre cleavage factor like coiled coil inserts deep into the RNAP secondary channel, dismantling the active site and displacing RNA, while a unique helical protrusion inserts into the main channel, prying the amp; 946; and amp; 946; amp; 8242; subunits apart and, aided by amp; 948;, dislodging DNA. RNAP is recycled when, after releasing trapped nucleic acids, HelD dissociates from the enzyme in an ATP dependent manner. HelD abundance during slow growth and a dimeric RNAP amp; 948; HelD 2 structure that resembles hibernating eukaryotic RNAP I suggest that HelD might also modulate active enzyme pools in response to cellular cue

Synthesis, NMR spectra and X-ray data of chloro and dichloro derivatives of 3-hydroxy-2-phenylquinolin-4(1H)-ones and their cytostatic activity

As known, some derivatives of quinolin-4(1H)-one possess interesting biological properties. The biological and cytostactic activity of 2-substituted 3-hydroxyquinolin-4(1H)-ones has not been reported yet. In this paper the synthesis of a series of chloro and dichloro 2-phenyl-3-hydroxyquinolin-4(1H)-ones and their characterization by NMR spectra and X-ray data is described. Their cytostatic properties have been evaluated and the results are reported