Effect of rfaH (sfrB) and temperature on expression of rfa genes of Escherichia coli K-12

Pradel, Elizabeth; Schnaitman, Carl A.

doi:10.1128/jb.173.20.6428-6431.1991

Cited by 71 publications

(80 citation statements)

References 14 publications

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“…It is possible that both the kdtA gene and the 18-kDa gene downstream from it (2) and the long block of contiguous genes beginning with rfaQ (1) are operons. The intergene region may also be necessary for the action of sfrB (rfaH), which is a positive regulator of rfaQ and the genes (rfaGPBJ) which lie downstream from it (13 35,000 a Apparent molecular weight of the in vitro translation product on gels, from reference 1. cant length. The coding region of the three genes is also A+T rich, at 54.8, 55.1, and 56.4% A+T, respectively, for rfaQ, rfaG and rfaP.…”

Section: Resultsmentioning

confidence: 99%

Identification and sequences of the lipopolysaccharide core biosynthetic genes rfaQ, rfaP, and rfaG of Escherichia coli K-12

1992

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The rfa locus of Escherichia coli K-12 includes a block of about 10 closely spaced genes transcribed in the same direction which are involved in synthesis and modification of the hexose region of the llpopolysaccharide core. We have sequenced the first three genes in this block. The function of the first of these genes is unknown, but we have designated it rfaQ on the basis of its location and similarity to other rfa genes. Complementation of SalmoneUa typhimurium rfa mutants with E. coli rfa restriction fragments indicated that the second and third genes in the block were rfaG and rfaP. The deduced sizes of the RfaQ, RfaG, and RfaP proteins are 36,298, 42,284, and 30,872 Da, respectively, and the proteins are basic and lack extensive hydrophobic domins. RfaQ shares regions of homology with proteins RfaC and RfaF, which are involved in synthesis of the heptose region of the core. Proteins RfaB, RfaG, and RfaK share a region of homology, which suggests that they belong to a second family of Rfa proteins which are thought to be hexose transferases.This study deals with rfaG, the gene for addition of the first glucose residue to the lipopolysaccharide (LPS) core, and with rfaP, a gene involved in attachment of phosphatecontaining substituents to the inner core. Figure 1 shows a simplified structure of the inner core region of Salmonella typhimurium and what are thought to be the primary sites of action of the relevant rfa genes (8). It can be assumed that this part of the core structure is very similar or identical in Escherichia coli K-12, since cloned DNA fragments from E. coli K-12 efficiently complement mutations in rfaC, rfaF, and rfaG in S. typhimurium (3,12).Two E. coli K-12 recombinant plasmids from the ClarkeCarbon collection, pLC10-7 and pLC17-24, were identified by Creeger and Rothfield as containing inserts which would complement rfaG mutations in S. typhimurium (3). The inserts of these plasmids overlap by about 4 kb, and the region of overlap includes two HindIII sites near the pyrE end of the rfa locus at 81 min on the E. coli map (1). In vitro transcription and translation of restriction fragments derived from the insert of pLC10-7 showed that these Hindlll sites lie at the beginning of a series of contiguous genes which are transcribed counterclockwise from pyrE. The in vitro products of the first three of these genes, reading away from pyrE, had apparent molecular masses of 42, 39, and 35 kDa. TnJO insertions in the second gene resulted in a glucosedeficient LPS (chemotype Rd1) phenotype, suggesting that this is the rfaG gene, while an insertion in the third gene resulted in a deep rough phenotype and LPS of the RcPchemotype, which includes the first glucose residue. These properties suggest that this gene is rfaP (1).In this report, we describe the sequence and properties of these three genes and show, by complementation of Salmonella mutations, that two of them are indeed rfaG and rfaP. The other is a novel gene, which we designated rfaQ. The relationship of these genes to the physical map of ...

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Section: Resultsmentioning

confidence: 99%

Identification and sequences of the lipopolysaccharide core biosynthetic genes rfaQ, rfaP, and rfaG of Escherichia coli K-12

1992

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“…For screening purposes LPS was obtained after proteinase K digestion of whole cells (20). LPS samples were separated by SDS-PAGE or Tricine-SDS-PAGE and visualized by silver staining as described previously (21,22).…”

Section: Methodsmentioning

confidence: 99%

The Incorporation of Glucosamine into Enterobacterial Core Lipopolysaccharide

Regué

Izquierdo

Fresno

et al. 2005

Journal of Biological Chemistry

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The core lipopolysaccharide (LPS) of Klebsiella pneumoniae is characterized by the presence of disaccharide ␣GlcN-(1,4)-␣GalA attached by an ␣1,3 linkage to L-glycero-D-manno-heptopyranose II (LD-HeppII). Previously it has been shown that the WabH enzyme catalyzes the incorporation of GlcNAc from UDP-GlcNAc to outer core LPS. The presence of GlcNAc instead of GlcN and the lack of UDP-GlcN in bacteria indicate that an additional enzymatic step is required. In this work we identified a new gene (wabN) in the K. pneumoniae core LPS biosynthetic cluster. Chemical and structural analysis of K. pneumoniae non-polar wabN mutants showed truncated core LPS with GlcNAc instead of GlcN. In vitro assays using LPS truncated at the level of D-galacturonic acid (GalA) and cell-free extract containing WabH and WabN together led to the incorporation of GlcN, whereas none of them alone were able to do it. This result suggests that the later enzyme (WabN) catalyzes the deacetylation of the core LPS containing the GlcNAc residue. Thus, the incorporation of the GlcN residue to core LPS in K. pneumoniae requires two distinct enzymatic steps. WabN homologues are found in Serratia marcescens and some Proteus strains that show the same disaccharide ␣GlcN-(1,4)-␣GalA attached by an ␣1,3 linkage to LD-HeppII.

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“…RfaH controls the expression of OAg and core oligosaccharide biosynthesis genes (Bailey et al, 1997;Pradel & Schnaitman, 1991;Wang et al, 1998).…”

Section: Introductionmentioning

confidence: 99%

O-antigen modal chain length in Shigella flexneri 2a is growth-regulated through RfaH-mediated transcriptional control of the wzy gene

et al. 2007

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Effect of rfaH (sfrB) and temperature on expression of rfa genes of Escherichia coli K-12

Cited by 71 publications

References 14 publications

Identification and sequences of the lipopolysaccharide core biosynthetic genes rfaQ, rfaP, and rfaG of Escherichia coli K-12

Identification and sequences of the lipopolysaccharide core biosynthetic genes rfaQ, rfaP, and rfaG of Escherichia coli K-12

The Incorporation of Glucosamine into Enterobacterial Core Lipopolysaccharide

O-antigen modal chain length in Shigella flexneri 2a is growth-regulated through RfaH-mediated transcriptional control of the wzy gene

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