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Biosynthesis and Genetics of Lipopolysaccharide Core
Published in Helmut Brade, Steven M. Opal, Stefanie N. Vogel, David C. Morrison, Endotoxin in Health and Disease, 2020
David E. Heinrichs, Chris Whitfield, Miguel A. Valvano
The core OS biosynthesis gene cluster consists of three operons (Fig. 6), which we will refer to as the gmhD-, waaQ-, and waaA-containing operons, an assignment based on the first gene of the transcriptional unit. Below, we describe the factors involved in the regulation of these operons and discuss implications for coordinated regulation of cell-surface components.
Reactivities of Amino Acids and Proteins with Iodine
Published in Erwin Regoeczi, Iodine-Labeled Plasma Proteins, 2019
The lactose repressor protein binds specifically to the lac operon, and prevents the tran- scription of the lac structural genes by preventing the movement of promotor-bound RNA polymerase through the operator region. This protein loses both its specific and nonspecific DNA-binding capability when Tyr-7 and Tyr-17 (both situated in the N-terminus) are mod- ified by tetranitromethane. Conversion of the affected residues to aminotyrosyls restores partial operator DNA-binding and complete nonspecific DNA-binding capability362 (See also Chapter 3, Section H.F.2.)
O
Published in Anton Sebastian, A Dictionary of the History of Medicine, 2018
Operon [Latin: opera, work; Greek: on] Genetic unit that coordinates expression from DNA to messenger RNA. Discovered and named by François Jacob (b 1920), Sydney Brenner (b 1927), F. Cuzin and Jacques Lucien Monod (1910–1976) of France in 1963.
Molecules involved in motility regulation in Escherichia coli cells: a review
Published in Biofouling, 2020
Fazlurrahman Khan, Nazia Tabassum, Dung Thuy Nguyen Pham, Sandra Folarin Oloketuyi, Young-Mog Kim
The signaling mechanisms involved in flagellar motility and biofilm formation in E. coli are known to be inversely regulated (Simm et al. 2004). The regulation of flagellar motility in E. coli was also reported to occur at DNA, RNA, and protein levels (Figure 2A). The initiator of flagellar gene expression is the flagellar operon flhDC (which encodes a master flagellar regulator FlhDC). This operon is known to be highly regulated at DNA, mRNA, and protein levels by various regulatory molecules. The promoter of flhDC contains multiple binding sites for transcriptional regulators that may increase or decrease gene expression (Lehnen et al. 2002). Some of these transcriptional regulators were also found to regulate the expression of genes involved in the formation of biofilm components (Figure 2A).
Stenotrophomonas maltophilia biofilm: its role in infectious diseases
Published in Expert Review of Anti-infective Therapy, 2019
Samantha Flores-Treviño, Paola Bocanegra-Ibarias, Adrián Camacho-Ortiz, Rayo Morfín-Otero, Humberto Antonio Salazar-Sesatty, Elvira Garza-González
QS was first described in Xanthomonas campestris pv. campestris as a regulation mechanism of virulence. The components of this QS system are encoded by the rpf cluster. Genes within this cluster include enzymes for the synthesis, perception, and signal transduction of DSF. The rpf (regulation of pathogenicity factors) cluster is organized in two adjacent operons convergently transcribed. One operon includes the genes that encode an aconitase, RpfA; a fatty acyl-CoA ligase, RpfB; and an enoyl coenzyme A hydratase, DSF synthase RpfF. The other operon is a two-component system that encodes a hybrid histidine-kinase receptor and effector, RpfC and a cytoplasmic regulator, RpfG. The synthesis of DSF depends on RpfF, whose activity is regulated by RpfC. Recognition of DSF by RpfC is linked to RpfG and alteration in the level of c-di-GMP [43].
Chaperonomics in leptospirosis
Published in Expert Review of Proteomics, 2018
Arada Vinaiphat, Visith Thongboonkerd
A conserved inverted repeat (TTAGCACTC-N9-GAGTGCTAA), also known as the Controlling Inverted Repeat of Chaperone Expression (CIRCE) regulon, has been found at the upstream of some major heat shock operons of groE, dnaK, and dnaJ genes. This regulon plays an important role in controlling gene expression by serving as a target of transcriptional repressor [64,65]. HrcA is an example of the repressor that interacts with CIRCE regulon of heptacistronic dnaK and bicistronic groE operons in B. subtilis [64,66]. Another well studied organism that serves as a model for heat shock response in Gram-positive bacteria is Streptomyces. Three distinct transcriptional machinery systems of heat shock regulons present in this bacterium are under negative control of three different transcriptional repressors designated as HrcA, RheA, and HspR [63]. Although this existing regulatory response has been demonstrated in several bacterial groups, it should be noted that other elements and additional levels of operon regulation may also exist in different species.