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Potential regulatory interactions of Escherichia coli RraA protein with DEAD-box helicases.

Pietras Z, Hardwick SW, Swiezewski S, Luisi BF - J. Biol. Chem. (2013)

Bottom Line: We present structural and biochemical evidence showing how RraA can bind to, and modulate the activity of RhlB and another E. coli DEAD-box enzyme, SrmB.Crystallographic structures are presented of RraA in complex with a portion of the natively unstructured C-terminal tail of RhlB at 2.8-Å resolution, and in complex with the C-terminal RecA-like domain of SrmB at 2.9 Å.The models suggest two distinct mechanisms by which RraA might modulate the activity of these and potentially other helicases.

View Article: PubMed Central - PubMed

Affiliation: From the Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1GA, United Kingdom and.

ABSTRACT
Members of the DEAD-box family of RNA helicases contribute to virtually every aspect of RNA metabolism, in organisms from all domains of life. Many of these helicases are constituents of multicomponent assemblies, and their interactions with partner proteins within the complexes underpin their activities and biological function. In Escherichia coli the DEAD-box helicase RhlB is a component of the multienzyme RNA degradosome assembly, and its interaction with the core ribonuclease RNase E boosts the ATP-dependent activity of the helicase. Earlier studies have identified the regulator of ribonuclease activity A (RraA) as a potential interaction partner of both RNase E and RhlB. We present structural and biochemical evidence showing how RraA can bind to, and modulate the activity of RhlB and another E. coli DEAD-box enzyme, SrmB. Crystallographic structures are presented of RraA in complex with a portion of the natively unstructured C-terminal tail of RhlB at 2.8-Å resolution, and in complex with the C-terminal RecA-like domain of SrmB at 2.9 Å. The models suggest two distinct mechanisms by which RraA might modulate the activity of these and potentially other helicases.

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The solution and crystal structures of the SrmB-RraA complex.A, an averaged ab initio SAXS model of SrmB-RraA complex, shown from two viewpoints related by a 90° rotation. B, the content of the crystal asymmetric unit (two viewpoints related by a 90° rotation, as in A). The RraA trimer is colored salmon with the protomer contacting SrmB shown in red, SrmB CTD is shown in blue. The N and C termini of SrmB are marked by N and C, respectively.
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Figure 2: The solution and crystal structures of the SrmB-RraA complex.A, an averaged ab initio SAXS model of SrmB-RraA complex, shown from two viewpoints related by a 90° rotation. B, the content of the crystal asymmetric unit (two viewpoints related by a 90° rotation, as in A). The RraA trimer is colored salmon with the protomer contacting SrmB shown in red, SrmB CTD is shown in blue. The N and C termini of SrmB are marked by N and C, respectively.

Mentions: To obtain insights into how the interaction of RraA with SrmB might influence the activity of the helicase, we obtained solution and crystal structures of this complex. We first performed SAXS to obtain the low-resolution envelope for the complex formed by mixing SrmB and RraA at a 1:3 molar ratio. This envelope can accommodate a single RraA trimer with a single SrmB helicase bound to the outer ring of RraA, consistent with the 1:3 molar ratio indicated by analytical ultracentrifugation analyses (Fig. 2A).


Potential regulatory interactions of Escherichia coli RraA protein with DEAD-box helicases.

Pietras Z, Hardwick SW, Swiezewski S, Luisi BF - J. Biol. Chem. (2013)

The solution and crystal structures of the SrmB-RraA complex.A, an averaged ab initio SAXS model of SrmB-RraA complex, shown from two viewpoints related by a 90° rotation. B, the content of the crystal asymmetric unit (two viewpoints related by a 90° rotation, as in A). The RraA trimer is colored salmon with the protomer contacting SrmB shown in red, SrmB CTD is shown in blue. The N and C termini of SrmB are marked by N and C, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3814787&req=5

Figure 2: The solution and crystal structures of the SrmB-RraA complex.A, an averaged ab initio SAXS model of SrmB-RraA complex, shown from two viewpoints related by a 90° rotation. B, the content of the crystal asymmetric unit (two viewpoints related by a 90° rotation, as in A). The RraA trimer is colored salmon with the protomer contacting SrmB shown in red, SrmB CTD is shown in blue. The N and C termini of SrmB are marked by N and C, respectively.
Mentions: To obtain insights into how the interaction of RraA with SrmB might influence the activity of the helicase, we obtained solution and crystal structures of this complex. We first performed SAXS to obtain the low-resolution envelope for the complex formed by mixing SrmB and RraA at a 1:3 molar ratio. This envelope can accommodate a single RraA trimer with a single SrmB helicase bound to the outer ring of RraA, consistent with the 1:3 molar ratio indicated by analytical ultracentrifugation analyses (Fig. 2A).

Bottom Line: We present structural and biochemical evidence showing how RraA can bind to, and modulate the activity of RhlB and another E. coli DEAD-box enzyme, SrmB.Crystallographic structures are presented of RraA in complex with a portion of the natively unstructured C-terminal tail of RhlB at 2.8-Å resolution, and in complex with the C-terminal RecA-like domain of SrmB at 2.9 Å.The models suggest two distinct mechanisms by which RraA might modulate the activity of these and potentially other helicases.

View Article: PubMed Central - PubMed

Affiliation: From the Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1GA, United Kingdom and.

ABSTRACT
Members of the DEAD-box family of RNA helicases contribute to virtually every aspect of RNA metabolism, in organisms from all domains of life. Many of these helicases are constituents of multicomponent assemblies, and their interactions with partner proteins within the complexes underpin their activities and biological function. In Escherichia coli the DEAD-box helicase RhlB is a component of the multienzyme RNA degradosome assembly, and its interaction with the core ribonuclease RNase E boosts the ATP-dependent activity of the helicase. Earlier studies have identified the regulator of ribonuclease activity A (RraA) as a potential interaction partner of both RNase E and RhlB. We present structural and biochemical evidence showing how RraA can bind to, and modulate the activity of RhlB and another E. coli DEAD-box enzyme, SrmB. Crystallographic structures are presented of RraA in complex with a portion of the natively unstructured C-terminal tail of RhlB at 2.8-Å resolution, and in complex with the C-terminal RecA-like domain of SrmB at 2.9 Å. The models suggest two distinct mechanisms by which RraA might modulate the activity of these and potentially other helicases.

Show MeSH
Related in: MedlinePlus