Learning new tricks from an old dog: MalT of the Escherichia coli maltose system is part of a complex regulatory network

Boos, Winfried; Böhm, Alex

doi:10.1016/s0168-9525(00)02086-2

Cited by 64 publications

(95 citation statements)

References 38 publications

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“…The G346S substitution, which is thought to alter the MalT-binding site, specifically decreases the ability of MalK to down-regulate MalT in vivo without damaging its ability to catalyze maltose transport both when overproduced or when constitutively expressed from a chromosomal locus (10). 4 As expected, MalT is not inhibited by the MalK-G346S variant in the presence of 2 AMP-PNP, which can replace ATP as an effector of MalT (33), is actually more effective than ATP in driving MalT self-association in the presence of maltotriose due to the absence of ATP hydrolysis, which generates ADP-bound forms that are less prone to multimerization (16). 3 MalT is 50% as active in the presence of AMP-PNP alone as it is in the presence of AMP-PNP and a saturating concentration of maltotriose.…”

Section: Malt and Malk Mutations Relieving Malt Inhibition By Malk Inmentioning

confidence: 99%

“…This paper deals with the roles that ATP-binding cassette transporters play in signaling pathways. The model system is the Escherichia coli maltodextrin transporter, whose ATPbinding cassette component, the MalK protein, down-regulates the activity of MalT, a transcriptional activator that controls the expression of the maltose regulon (4). MalT control by MalK was first recognized with the finding that malK null mutants express constitutively the maltose regulon, whereas MalK overproduction blocks mal gene induction (5,6).…”

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confidence: 99%

“…Transcription activation by MalT involves MalT self-association, cooperative binding to an array of MalT sites located in the target promoters, and stimulation of open complex formation by the RNA polymerase (14 -16). A complex interplay of signaling compounds and proteins controls the activity of the MalT protein (4). MalT is active only in the presence of ATP and maltotriose, both of which are required for multimerization (16).…”

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confidence: 99%

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MalK, the ATP-binding Cassette Component of the Escherichia coli Maltodextrin Transporter, Inhibits the Transcriptional Activator MalT by Antagonizing Inducer Binding

Joly

Böhm

Boos

et al. 2004

Journal of Biological Chemistry

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Section: Malt and Malk Mutations Relieving Malt Inhibition By Malk Inmentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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MalK, the ATP-binding Cassette Component of the Escherichia coli Maltodextrin Transporter, Inhibits the Transcriptional Activator MalT by Antagonizing Inducer Binding

Joly

Böhm

Boos

et al. 2004

Journal of Biological Chemistry

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“…Besides BirA and XylR, GutR is another transcription regulator that binds the inducer/substrate and ATP in a sequential manner. Although GutR shares similarities to transcription activators such as MalT (20,21) and AcoK (22) in the 100-kDa transcription activator family in terms of their size, ATP binding capability, and the ability to activate transcription from the major RNA polymerase rather than the 54 containing RNA polymerase, none of the members in this family has been shown to bind the inducer and ATP in a sequential order. In fact, MalT binds ATP even in the absence of maltotriose (23).…”

Section: Table I Kinetic Association and Dissociation Rate Constants mentioning

confidence: 99%

Roles of Glucitol in the GutR-mediated Transcription Activation Process in Bacillus subtilis

Poon

Chu

Wong

2001

Journal of Biological Chemistry

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GutR is a 95-kDa glucitol-dependent transcription activator that mediates the expression of the Bacillus subtilis glucitol operon. Glucitol allows GutR to bind tightly to its binding site located upstream of the gut promoter. In this study, a second functional role of glucitol is identified. Glucitol induces GutR to change its conformation and triggers GutR to bind ATP efficiently. After sequential binding of glucitol and ATP to GutR, GutR adopts a new conformation by forming a compact structure that is resistant to trypsin digestion. Under this condition, the ATP⅐glucitiol⅐GutR complex can dissociate slowly from the gutR-binding site (t1 ⁄2 ‫؍‬ 274 min). Interestingly, if ATP in the ATP⅐glucitiol⅐GutR complex is replaced by ADP, GutR adopts another conformation and can dissociate from the gutR-binding site even faster (t1 ⁄2 ‫؍‬ 82 min). In all these GutR-DNA binding studies in the presence of different ligands (glucitol, ATP, or ADP), only the off-rate is affected. The vital role of ATP in the GutRmediated transcription activation process is reflected by the poor transcription from the gut promoter with GutR(D285A) which has a mutation in the motif B of the putative ATP-binding site. A working model for this transcription activation process is presented.

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“…Although the sequence search of GutR did not find any known regulatory proteins that show significant homology to GutR, this protein shares some similarities to the properties of the members of the 100-kDa transcription activator family, such as MalT (23,24) and AcoK (25). They all are transcription activators with a molecular mass in the range of 100 kDa and there is a nucleotide binding site in each of these transcription activators.…”

Section: Figmentioning

confidence: 99%

Roles of Glucitol in the GutR-mediated Transcription Activation Process in Bacillus subtilis

Poon¹,

Chen

Wong

2001

Journal of Biological Chemistry

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Glucitol induction in Bacillus subtilis requires a transcription activator, GutR, and a sequence located upstream of the gut promoter. To understand the initial steps involved in the GutR-mediated transcription activation process and the physiological roles of glucitol, GutR was overproduced and purified. In the absence of glucitol, GutR exists as a monomer and binds directly to its binding site in the gut regulatory region. This binding site was mapped to a 29-base pair imperfect inverted repeat located between ؊78 and ؊50, and there is only one GutR binding site within the regulatory region. The kinetic parameters of the interaction between GutR and its binding site were monitored in real time using surface plasmon resonance. The half-life of the GutR-DNA complex in the absence of glucitol was estimated to be 6.8 min. In contrast, in the presence of glucitol, the halflife of the complex was extended to longer than 19 h by affecting only the off-rate but not the on-rate. This effect is glucitol-specific. These data indicate that glucitol binds to GutR and induces GutR to have an extremely tight binding at its binding site. The physiological relevance of this process in transcription activation is discussed.With the addition of glucitol to Bacillus subtilis, a set of glucitol-inducible genes is selectively turned on (1). These inducible genes include gutA-and gutB-encoding glucitol permease and glucitol dehydrogenase, respectively. They are the members of the gut (glucitol utilization) operon and are arranged in the order from gutB to gutA. This operon is subject to both negative and positive regulations at the transcription level with the positive regulation playing a major role in the induction process. The regulatory region of the gut operon can be divided into three parts (2). The central portion is an unusual promoter with its Ϫ10 and Ϫ35 elements similar to those recognized by the major RNA polymerase (E A ) separated from each other by a 15-bp 1 spacer rather than a typical 17-bpspacer. An inverted repeat sequence located downstream of the promoter serves as a negative regulatory element (2). Although deletion of this sequence does not result in the constitutive expression of the gut operon in the absence of glucitol, the induced expression from this system increases by almost 4-fold. A region (from Ϫ126 to Ϫ48 with the transcription start site as ϩ1) located upstream of the promoter is required for glucitol induction and is suggested to contain binding sites for a transcription activator, GutR. The structural gene encoding GutR is located upstream of the gut operon and is transcribed in an opposite direction relative to that of the gut operon (3, 4

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Learning new tricks from an old dog: MalT of the Escherichia coli maltose system is part of a complex regulatory network

Cited by 64 publications

References 38 publications

MalK, the ATP-binding Cassette Component of the Escherichia coli Maltodextrin Transporter, Inhibits the Transcriptional Activator MalT by Antagonizing Inducer Binding

MalK, the ATP-binding Cassette Component of the Escherichia coli Maltodextrin Transporter, Inhibits the Transcriptional Activator MalT by Antagonizing Inducer Binding

Roles of Glucitol in the GutR-mediated Transcription Activation Process in Bacillus subtilis

Roles of Glucitol in the GutR-mediated Transcription Activation Process in Bacillus subtilis

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