Hydrodynamic properties of colicin A

Cavard, D; Sauve, Paul; Heitz, Fréderic; Pattus, Franc; Martinez, C.; Dijkman, R.; Lazdunski, Claude

doi:10.1111/j.1432-1033.1988.tb13916.x

Cited by 25 publications

(18 citation statements)

References 34 publications

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“…Axial ratios ranging from 7 to 20 were found for colicins E2, E3, Ia, and Ib, with I colicins being more elongated (358). Further hydrodynamic analyses of colicin A have shown that it forms tetramers at acidic pHs and that while full-length colicin A is an asymmetric molecule, the isolated translocation domain is globular (102,345). The structure of the C-terminal domain of colicin A has been solved by X-ray crystallography, in part due to the emergent technique of sitedirected mutagenesis.…”

Section: Three-dimensional Structures Of Colicinsmentioning

confidence: 99%

Colicin Biology

Cascales

Buchanan

Duché

et al. 2007

Microbiol Mol Biol Rev

971

1,324

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SUMMARY Colicins are proteins produced by and toxic for some strains of Escherichia coli. They are produced by strains of E. coli carrying a colicinogenic plasmid that bears the genetic determinants for colicin synthesis, immunity, and release. Insights gained into each fundamental aspect of their biology are presented: their synthesis, which is under SOS regulation; their release into the extracellular medium, which involves the colicin lysis protein; and their uptake mechanisms and modes of action. Colicins are organized into three domains, each one involved in a different step of the process of killing sensitive bacteria. The structures of some colicins are known at the atomic level and are discussed. Colicins exert their lethal action by first binding to specific receptors, which are outer membrane proteins used for the entry of specific nutrients. They are then translocated through the outer membrane and transit through the periplasm by either the Tol or the TonB system. The components of each system are known, and their implication in the functioning of the system is described. Colicins then reach their lethal target and act either by forming a voltage-dependent channel into the inner membrane or by using their endonuclease activity on DNA, rRNA, or tRNA. The mechanisms of inhibition by specific and cognate immunity proteins are presented. Finally, the use of colicins as laboratory or biotechnological tools and their mode of evolution are discussed.

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Section: Three-dimensional Structures Of Colicinsmentioning

confidence: 99%

Colicin Biology

Cascales

Buchanan

Duché

et al. 2007

Microbiol Mol Biol Rev

971

1,324

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“…The analytical centrifugation experiments indicated the oligomeric state of the proteins. TolAIII and TolAII were monomeric in solution (data not shown), as was colicin A (Cavard et al, 1988) and its N-terminal domain (Knibiehler et al, 1989).…”

Section: Estimation Of the Kinetic Values Of Colicin Binding To Immobmentioning

confidence: 99%

Binding of colicins A and E1 to purified ToIA domains

Derouiche

Zeder‐Lutz²,

Bénédetti

et al. 1997

Microbiology

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Colicins are divided into two groups according t o the proteins required for their import into sensitive bacteria. The To1 and TonB pathways are involved in import of group A and group B colicins respectively. Because previous analyses have shown that colicin E l and colicin A (two group A colicins) interact in witro with the C-terminal domain of TolA (TolAlll) while colicin B (group B colicin) does not, attention was focused on these interactions with purified proteins.TolA has been described as a threcdomain protein with an N-terminal innermembrane anchor and a long periplasmic region formed by two domains (TolAII and TolAlll). TolAIII, TolAll and TolAII-Ill soluble domains with an Nterminal hexa-histidine extension were purified. The interactions of colicins with the purified TolA domains were analysed by overlay Western blotting, which indicated that both N-terminal domains of colicins A and E l interacted with TolAIII, while a gel shift procedure detected no interaction with colicin El. The binding kinetic values of the N-terminal domains of colicins A and E l t o TolAlll were estimated by surface plasmon resonance and were shown t o be similar.

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“…The intact colicin A was found to be highly asymetric [3] while the AT1 protein which accounts for about a third of the entire molecule is not asymetric with an axial ratio of about 2.4. In contrast, the 20-kDa C-terminal domain is highly structured [l, 2.…”

Section: Discussionmentioning

confidence: 99%

“…The AT1 protein also has little affinity for phospholipid monolayers, despite the fact that colicin A itself displays strong affinity for lipids [3,161. Colicin A derivatives which lack the N-terminal domain can both bind to receptors and form ion channels in vitro but cannot kill sensitive cells [I, 51. Since the N-terminal domain is required for transport of colicin A across the outer membrane, it is tempting to speculate that the role of this region of the colicin involves its interaction with cellular components which function to transport it to the inner membrane.…”

Section: Discussionmentioning

confidence: 99%

“…The sites of cleavage by SmaI and SnaBT, the sequence at the junction and the position of the frameshift, are indicated and rotor temperature indication and control. Samples of the AT1 protein were dialyzed at 5°C for 24 h against buffer (10mM sodium phosphate pH 6.8) and analysis was performed as previously reported [3]. For determination of the axial ratio, the value of the sedimentation coefficient at infinite dilution ( s ;~,~) was calculated by extrapolation of si5.w values measured at different concentrations of AT1, using the least-squares method, and by measuring the specific mass and the viscosity (viscosimeter Ubbelohde, Schott Gerate) of the solution with respect to water at 25°C.…”

Section: Sedimentation Velocity and Determination Of The Axial Ratio mentioning

confidence: 99%

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Isolation and molecular and functional properties of the amino‐terminal domain of colicin A

Knibiehler¹,

Howard²,

Baty³

et al. 1989

European Journal of Biochemistry

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A plasmid was constructed which allowed easy and efficient production and purification of the NH2-terminal domain of colicin A. In only three steps, an homogenous 18-kDa polypeptide was obtained. The NH2-and COOH-terminal sequences of the protein were determined and showed that it corresponded to the NH2-terminal 171 amino acid residues of the 63-kDa colicin A. Although colicin A is a highly asymmetric protein, hydrodynamic studies indicated that the NH2-terminal domain (designated AT) has a globular structure. This fragment is not the receptor-binding domain of colicin A but is required for the transfer of colicin A across the outer membrane of sensitive cells. However, it has a low affinity for phospholipid films and this affinity is not pH-dependent, in contrast to that of colicin A.Colicins are antibiotic proteins produced by strains of MATERIALS AND METHODS Enterobacteriaceae. The major group of colicins is composed of by those such as A, B, El, K, N, Ia and Ib which collapse the membrane potential, presumably by forming ion channels in the inner membrane (for a review, see Lazdunski et al. [l]).The mode of action of colicins appears to involve three steps: (a) binding to a specific receptor located in the outer membrane; (b) translocation across the membrane(s); and (c) biochemical interaction of the colicin with its target in the cell.Colicin A is a 63-kDa protein for which the primary sequence has been deduced from the nucleotide sequence of the caa gene [2]. It is a highly asymmetric molecule with an axial ratio of 9.6 for a flat ellipsoid [3].Using a molecular genetic approach, we have previously demonstrated that the NH2-terminal domain is involved in translocation across the outer membrane, that the central region is involved in receptor binding, and that the COOH-terminal domain has the channel-forming activityThe COOH-terminal domain of colicin A has previously been obtained by limited digestion with bromelain or thermolysin and purified [4]. This 20-kDa fragment displays ionophoric activity in vitro [4]. It has been crystallized [6] and its three-dimensional structure at 0.27-nm resolution has been resolved [7]. In order to understand fully the mechanism of action of the multi-functional colicin A molecule, it is useful to purify and study each of its domains individually. In this study, we have made a construct which allows high-level synthesis of the NH,-terminal domain of colicin A. Using the construct, we have been able to purify this domain and study its functional and molecular properties. Bacterial strains, plasmids and growth conditionsThe bacterial host strain W3110 grown in Luria broth medium and the plasmid pColA9 (derived from wild-type pColA) have been previously described [8]. Colicin A and AT1 synthesis were induced with 300 ng/ml of mitomycin C at an absorbance at 600 nm of 1. Construction of PATIThe enzymes SmaI and SnaBl were purchased from Boehringer-Mannheim and used to digest pColA9, which was then self-ligated to yield pATl. Colicin purification and assayColicin A was purifi...

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Hydrodynamic properties of colicin A

Cited by 25 publications

References 34 publications

Colicin Biology

Colicin Biology

Binding of colicins A and E1 to purified ToIA domains

Isolation and molecular and functional properties of the amino‐terminal domain of colicin A

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