Receptor structure in the bacterial sensing system.

Wang, Elizabeth A.; Koshland, Daniel E.

doi:10.1073/pnas.77.12.7157

Cited by 107 publications

(60 citation statements)

References 32 publications

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“…These transmembrane proteins function as receptors for many chemostimuli and therefore are responsible for binding to specific attractant and repellent molecules and for communicating (signaling) these binding events to the cellular machinery that determines the swimming behavior of the cell (6,10,11,21,22,26,39,61 only by its interactions with attractants and repellents, but also by the methylation of several of its glutamic acid residues (12-14, 35, 36, 49). Methylation of the transducer proteins is catalyzed by a chemotaxis-specific methyltransferase (CheR) (49), which utilizes S-adenosylmethionine as the methyl donor and generates the corresponding methyl esters of specific glutamate residues of the transducers.…”

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confidence: 99%

N-terminal half of CheB is involved in methylesterase response to negative chemotactic stimuli in Escherichia coli

Stewart

Dahlquist

1988

J Bacteriol

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The chemotactic receptor-transducer proteins of Escherichia coli are responsible for directing the swimming behavior of cells by signaling for either straight swimming or tumbling in response to chemostimuli. The signaling states of these proteins are affected not only by the concentrations of various stimuli but also by the extent to which they have been methylated at specific glutamyl residues. The activities of a chemotaxis-specific methyltransferase (CheR) and a chemotaxis-specific methylesterase (CheB) (3,4,25).Among the cellular components that enable the chemotactic response and adaptation are the transducer proteins. These transmembrane proteins function as receptors for many chemostimuli and therefore are responsible for binding to specific attractant and repellent molecules and for communicating (signaling) these binding events to the cellular machinery that determines the swimming behavior of the cell (6,10,11,21,22,26,39,61 only by its interactions with attractants and repellents, but also by the methylation of several of its glutamic acid residues (12-14, 35, 36, 49). Methylation of the transducer proteins is catalyzed by a chemotaxis-specific methyltransferase (CheR) (49), which utilizes S-adenosylmethionine as the methyl donor and generates the corresponding methyl esters of specific glutamate residues of the transducers. A chemotaxis-specific methylesterase (CheB) catalyzes the hydrolysis of these methylesters, producing methanol and regenerating the glutamate carboxylate moieties (56). All of the transducer proteins are methylated to some extent, reflecting the relative activities of CheR and CheB. Transducer methylation levels change in response to chemostimuli (19,20,42,46 (12,13,(35)(36)(37)47).The methylesterase activity of CheB is modulated in response to chemotactic stimuli: attractants (such as serine) cause a transient decrease in methylesterase activity, whereas repellents (such as leucine) cause a transient activity increase (17,48,59). These activity changes are thought to play an important role in adjusting the signaling status of the transducer proteins to enable adaptation to occur. We 5728

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confidence: 99%

N-terminal half of CheB is involved in methylesterase response to negative chemotactic stimuli in Escherichia coli

Stewart

Dahlquist

1988

J Bacteriol

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“…Binding of an attractant to a chemoreceptor leads to inhibition of CheA (Borkovich et al, 1989), and hence decreases phosphorylation of CheB (Hess et al, 1988 ;Lupas & Stock, 1989) to decrease the rate of demethylation. The attractant-bound receptor becomes a better substrate for CheR and a poorer substrate for CheB, resulting in a net increase in methylation of the liganded receptor Wang & Koshland, 1980). Since the methylation levels of the class I revertant Tar proteins were lower than the methylation level of Tar-W550A, we conclude that the affinity of Tar for CheR was not restored by the class I suppressors.…”

Section: Discussionmentioning

confidence: 77%

Intragenic suppressors of a mutation in the aspartate chemoreceptor gene that abolishes binding of the receptor to methyltransferase

2002

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In the chemotaxis of Escherichia coli, receptor methylation is the key process of adaptation. The methyltransferase CheR binds to the carboxy-terminal NWETF sequence of major chemoreceptors. The substitution of Ala for Trp of this sequence (W550A) of the aspartate chemoreceptor (Tar) abolishes its CheRbinding ability. In this study, six independent intragenic suppressors of the mutation were isolated. They were divided into two classes. Tar carrying the class I suppressors (G278A-L488M, T334A, G278A, G278C and A398T) showed signal biases toward tumbling, corresponding to increased activities of the receptor-associated histidine kinase CheA. These suppressors further reduced the unstimulated methylation level of Tar-W550A, but allowed slight but significant stimulation of methylation by aspartate. Some other CheAactivating mutations were also found to serve as class I suppressors. These results suggest that the class I suppressors compensate for the signal bias of Tar-W550A caused by its low methylation level and that the NWETF sequence is required primarily to maintain an appropriate level of methylation by increasing the local concentration of CheR around the receptor. The class II suppressor was a mutation in the termination codon (Op554W) resulting in the addition of 11 residues containing an xWxxF motif. This revertant Tar supported chemotaxis and was methylated almost as effectively as wild-type Tar. This effect was reversed by introducing a mutation in the xWxxF motif. These results reinforce the importance of the xWxxF motif and suggest that the motif does not have to be located at the extreme carboxy terminus.

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“…First, the coding capacity of Xfla9l is not sufficient to account for both proteins. Second, methyl-accepting chemotaxis proteins are notoriously sensitive to proteolysis (16,30). We conclude, therefore, that there are no other FlbB/FlaI-dependent genes in the tsr region.…”

Section: Methodsmentioning

confidence: 97%

Chemotaxis in Escherichia coli: construction and properties of lambda tsr transducing phage

Callahan¹,

Frazier²,

Parkinson³

1987

J Bacteriol

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The tsr gene of Escherichia coli, located at approximately 99 min on the chromosomal map, encodes a methyl-accepting protein that -serves as the chemoreceptor and signal transducer for chemotactic responses to serine and several repellents. To determine whether any other chemotaxis or motility genes were located in the tsr region, we constructed and characterized two Xtsr RP437 (21). Primary strains are listed in Table 1. Other strains were constructed by transduction of desired mutations into one of the primary strains by using linked auxotrophic or drug resistance markers. Plasmids pLC8-9 (6), pAB100A&131, pAB100A133, and pAB100A139 (3) were obtained from A. Boyd. Xfla91 (25) was obtained from M. Silverman and carries the c1857 repressor mutation and a tsr insert derived from pLC8-9.

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Receptor structure in the bacterial sensing system.

Abstract: The primary receptors for aspartate and serine in bacterial chemotaxis have been shown to be the 60,000-dalton proteins encoded by the tar and tsr genes. The

Cited by 107 publications

References 32 publications

N-terminal half of CheB is involved in methylesterase response to negative chemotactic stimuli in Escherichia coli

N-terminal half of CheB is involved in methylesterase response to negative chemotactic stimuli in Escherichia coli

Intragenic suppressors of a mutation in the aspartate chemoreceptor gene that abolishes binding of the receptor to methyltransferase

Chemotaxis in Escherichia coli: construction and properties of lambda tsr transducing phage

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