E. coli trp Repressor Forms a Domain-Swapped Array in Aqueous Alcohol

Lawson, Catherine L.; Benoff, B.; Berger, Tatyana; Berman, Helen M.; Carey, Jannette

doi:10.1016/j.str.2004.03.019

Cited by 12 publications

(44 citation statements)

References 53 publications

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“…This repressor acts by binding at one or more of three operator sites located in the trp operon's promoter region (Fig. 2;Lawson et al 2004). The structures of the inactive trp aporepressor, the tryptophan-activated trp repressor, and the trp repressoroperator complex have all been determined, and this repressor's mechanism of action is well understood ( Fig.…”

Section: Findings the Tryptophan Biosynthetic Pathwaymentioning

confidence: 99%

“…2). Interactions between separate repressor molecules bound at adjacent trp operator sequences in the trp promoter increase the likelihood that each repressor molecule will remain bound at an operator, thereby increasing the degree of repression (Lawson et al 2004). The trp repressor also autoregulates its own synthesis, though weakly.…”

Section: Findings the Tryptophan Biosynthetic Pathwaymentioning

confidence: 99%

“…Interactions between trp repressor proteins bound at multiple adjacent operators in the trp promoter-operator region increase the stability of repressor-operator complexes, improving the effectiveness of repression ( Fig. 2; Lawson et al 2004). This figure was kindly drawn, and provided, by Dr. Andrzej Joachimiak.…”

Section: Findings the Tryptophan Biosynthetic Pathwaymentioning

confidence: 99%

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RNA-based regulation of genes of tryptophan synthesis and degradation, in bacteria

Yanofsky

2007

RNA

122

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We are now aware that RNA-based regulatory mechanisms are commonly used to control gene expression in many organisms. These mechanisms offer the opportunity to exploit relatively short, unique RNA sequences, in altering transcription, translation, and/or mRNA stability, in response to the presence of a small or large signal molecule. The ability of an RNA segment to fold and form alternative hairpin secondary structures-each dedicated to a different regulatory function-permits selection of specific sequences that can affect transcription and/or translation. In the present paper I will focus on our current understanding of the RNA-based regulatory mechanisms used by Escherichia coli and Bacillus subtilis in controlling expression of the tryptophan biosynthetic operon. The regulatory mechanisms they use for this purpose differ, suggesting that these organisms, or their ancestors, adopted different strategies during their evolution. I will also describe the RNA-based mechanism used by E. coli in regulating expression of its operon responsible for tryptophan degradation, the tryptophanase operon.

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Section: Findings the Tryptophan Biosynthetic Pathwaymentioning

confidence: 99%

Section: Findings the Tryptophan Biosynthetic Pathwaymentioning

confidence: 99%

Section: Findings the Tryptophan Biosynthetic Pathwaymentioning

confidence: 99%

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RNA-based regulation of genes of tryptophan synthesis and degradation, in bacteria

Yanofsky

2007

RNA

122

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“…The pores within the lattice have diameter ∼50 Å. A , C , and D are from Lawson et al (2004) (reprinted with permission from Elsevier © 2004); B is from Tasayco and Carey (1992) (reprinted with permission from the American Association for the Advancement of Science © 1992).…”

Section: Nature and Limits Of Reconstitutionmentioning

confidence: 99%

Protein reconstitution and three‐dimensional domain swapping: Benefits and constraints of covalency

et al. 2007

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The phenomena of protein reconstitution and three-dimensional domain swapping reveal that highly similar structures can be obtained whether a protein is comprised of one or more polypeptide chains. In this review, we use protein reconstitution as a lens through which to examine the range of protein tolerance to chain interruptions and the roles of the primary structure in related features of protein structure and folding, including circular permutation, natively unfolded proteins, allostery, and amyloid fibril formation. The results imply that noncovalent interactions in a protein are sufficient to specify its structure under the constraints imposed by the covalent backbone.

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“…As illustrated in Figure 1, there is pseudo-symmetry between the interactions of the N-terminal half of H3 (blue) and the C-terminal half of H4 (red) compared to the N-terminal half of H4 (purple) and the C-terminal half of H3 (cyan). In addition to mediating appropriate oligomerization, 3D domain swapping has been implicated in the propensity of proteins to aggregate into highly ordered structures such as crystals, 21 polymers, 22 fibers, 23 and fibrils. [24][25][26] Of particular interest is the possible connection between domain swapping and formation of amyloid or amyloid-like fibrils (for review see Ref.…”

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confidence: 99%

The impact of solubility and electrostatics on fibril formation by the H3 and H4 histones

Topping

Gloss

2011

Protein Science

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The goal of this study was to examine fibril formation by the heterodimeric eukaryotic histones (H2A-H2B and H3-H4) and homodimeric archaeal histones (hMfB and hPyA1). The histone fold dimerization motif is an obligatorily domain-swapped structure comprised of two fused helix:b-loop:helix motifs. Domain swapping has been proposed as a mechanism for the evolution of protein oligomers as well as a means to form precursors in the formation of amyloid-like fibrils. Despite sharing a common fold, the eukaryotic histones of the core nucleosome and archaeal histones fold by kinetic mechanisms of differing complexity with transient population of partially folded monomeric and/or dimeric species. No relationship was apparent between fibrillation propensity and equilibrium stability or population of kinetic intermediates. Only H3 and H4, as isolated monomers and as a heterodimer, readily formed fibrils at room temperature, and this propensity correlates with the significantly lower solubility of these polypeptides. The fibrils were characterized by ThT fluorescence, FTIR, and far-UV CD spectroscopies and electron microscopy. The helical histone fold comprises the protease-resistant core of the fibrils, with little or no protease protection of the poorly structured N-terminal tails. The highly charged tails inhibit fibrillation through electrostatic repulsion. Kinetic studies indicate that H3 and H4 form a co-fibril, with simultaneous incorporation of both histones. The potential impact of H3 and H4 fibrillation on the cytotoxicity of extracellular histones and a-synuclein-mediated neurotoxicity and fibrillation is considered.

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E. coli trp Repressor Forms a Domain-Swapped Array in Aqueous Alcohol

Cited by 12 publications

References 53 publications

RNA-based regulation of genes of tryptophan synthesis and degradation, in bacteria

RNA-based regulation of genes of tryptophan synthesis and degradation, in bacteria

Protein reconstitution and three‐dimensional domain swapping: Benefits and constraints of covalency

The impact of solubility and electrostatics on fibril formation by the H3 and H4 histones

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