MICRB316 Lecture Notes - Lecture 17: Dna-Binding Domain, Regulon, Antimicrobial Resistance
20 Mar 2016
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Document Summary
Multiple antibiotic resistance (mar) regulon- control center for producing abr. Antibiotic resistance frequently arises following acquisition of new dna carrying abr genes (plasmids, phage, tns)- acquired. Alternatively, it can arise through activation of a regulatory locus called mar (can turn on defensive mechanisms)- intrinsic or innate. Turning on extra genes alters the expression of multiple genes located on the bacterial chromosome produces resistance to antibiotics, organic solvents, oxidative stress agents, household disinfectants *don"t kill cell but inhibit. The regulation is compromised of 2 tn units marc & marrab. Divergent promoters; marc= inner mb protein unknown fxn; marr= repressor; mara= activator; marb= small protein, unknown fx. Marc on one side and a, b on the other site in the middle: binding site for regulators. In e. coli marrab is induced by tet, cm, salicylate- salicylic acid- plant molecule for hypersensitivity. (all unrelated compounds). Under non-inducing conditions, a marr dimer binds 2 direct maro repeats (operator) and represses tn of marrab.
