https://nova.newcastle.edu.au/vital/access/ /manager/Index ${session.getAttribute("locale")} 5 ε, a new subunit of RNA polymerase found in gram-positive bacteria https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:20794 Firmicutes phylum of Gram-positive bacteria and have named it ε. Previously ε had been identified as a small protein (ω1) that copurified with RNA polymerase. We have solved the structure of ε by X-ray crystallography and show that it is not an ω subunit. Rather, ε bears remarkable similarity to the Gp2 family of phage proteins involved in the inhibition of host cell transcription following infection. Deletion of ε shows no phenotype and has no effect on the transcriptional profile of the cell. Determination of the location of ε within the assembly of RNA polymerase core by single-particle analysis suggests that it binds toward the downstream side of the DNA binding cleft. Due to the structural similarity of ε with Gp2 and the fact they bind similar regions of RNA polymerase, we hypothesize that ε may serve a role in protection from phage infection.]]> Wed 11 Apr 2018 09:30:37 AEST ]]> Robenidine analogues as gram-positive antibacterial agents https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:30033 1 (2,2′-bis[(4-chlorophenyl)methylene]carbonimidic dihydrazide), was active against MRSA and VRE with MIC’s of 8.1 and 4.7 μM, respectively. SAR revealed tolerance for 4-Cl isosteres with 4-F (8), 3-F (9), 3-CH₃ (22), and 4-C(CH₃)₃ (27) (23.7–71 μM) and with 3-Cl (3), 4-CH₃ (21), and 4-CH(CH₃)₂ (26) (8.1–13.0 μM). Imine carbon alkylation identified a methyl/ethyl binding pocket that also accommodated a CH₂OH moiety (75; 2,2′-bis[1-(4-chlorophenyl)-2-hydroxyethylidene]carbonimidic dihydrazide). Analogues 1, 27 (2,2′-bis{[4-(1,1-dimethylethyl)phenyl]methylene}carbonimidic dihydrazide), and 69 (2,2′-bis[1-(4-chlorophenyl)ethylidene]carbonimidic dihydrazide hydrochloride) were active against 24 clinical MRSA and MSSA isolates. No dose-limiting cytotoxicity at ≥2× MIC or hemolysis at ≥8× MIC was observed. Polymyxin B addition engendered Escherichia coli and Pseudomonas aeruginosa Gram-negative activity MIC’s of 4.2–21.6 μM. 1 and 75 displayed excellent microsomal stability, intrinsic clearance, and hepatic extraction ratios with T1/2 > 247 min, CLint < 7 μL/min/mg protein, and EH < 0.22 in both human and mouse liposomes for 1 and in human liposomes for 75.]]> Wed 02 Mar 2022 14:27:39 AEDT ]]> Impact of a Novel Anticoccidial Analogue on Systemic Staphylococcus aureus Infection in a Bioluminescent Mouse Model https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:45380 Thu 27 Oct 2022 15:58:15 AEDT ]]>