Molecular Mechanism of Transposase Activation by a Dedicated AAA+ ATPase Regulator

Core Concepts

Dedicated AAA+ ATPase regulators use nucleotide-controlled assembly and DNA deformation to enable structure-based site selectivity, transposase recruitment, and activation for chromosomal rearrangements and dissemination of genetic elements.

Abstract

The content describes the molecular mechanism by which a dedicated AAA+ ATPase regulator, IstB, activates the transposase IstA in the IS21 transposon system. Key insights: IstB self-assembles into an autoinhibited pentamer of dimers that tightly curves target DNA into a half-coil. Two IstB decamers dimerize, stabilizing the target DNA into a kinked S-shaped configuration that engages the IstA transposase at the interface between the two IstB oligomers. Specific interactions between IstB and IstA stimulate the ATPase activity of IstB and trigger a large conformational change in IstA, positioning its catalytic site to perform DNA strand transfer. This mechanism helps explain how AAA+ ATPase regulators, used by classical transposition systems like Tn7, Mu, and CRISPR-associated elements, can remodel their substrate DNA and cognate transposases to promote function.

Stats

Transposases drive chromosomal rearrangements and the dissemination of drug-resistance genes and toxins. Many transposases rely on dedicated AAA+ ATPase subunits that regulate site selectivity and catalytic function through poorly understood mechanisms.

Quotes

"Using IS21 as a model transposase system, we show how an ATPase regulator uses nucleotide-controlled assembly and DNA deformation to enable structure-based site selectivity, transposase recruitment, and activation and integration." "Solution and cryogenic electron microscopy studies show that the IstB ATPase self-assembles into an autoinhibited pentamer of dimers that tightly curves target DNA into a half-coil." "Two of these decamers dimerize, which stabilizes the target nucleic acid into a kinked S-shaped configuration that engages the IstA transposase at the interface between the two IstB oligomers to form an approximately 1 MDa transpososome complex."

Key Insights Distilled From

Molecular basis for transposase activation by a dedicated AAA+ ATPase - Nature

by Álva... at www.nature.com 06-26-2024

https://www.nature.com/articles/s41586-024-07550-6

Deeper Inquiries

How do the structural changes in IstB and IstA induced by ATP binding and hydrolysis regulate the timing and coordination of the transposition process?

The structural changes in IstB and IstA induced by ATP binding and hydrolysis play a crucial role in regulating the timing and coordination of the transposition process. When IstB ATPase binds ATP, it undergoes self-assembly into an autoinhibited pentamer of dimers, which leads to the tight curvature of target DNA. This conformational change in IstB facilitates the recruitment and activation of the IstA transposase. Subsequent hydrolysis of ATP by IstB triggers a large conformational change in IstA, positioning its catalytic site for DNA strand transfer. These coordinated structural changes induced by ATP binding and hydrolysis ensure the precise timing of transposase activation and integration, allowing for efficient transposition events.

What are the potential implications of this transposase activation mechanism for the development of novel antimicrobial strategies targeting mobile genetic elements?

The transposase activation mechanism involving IstB and IstA presents exciting implications for the development of novel antimicrobial strategies targeting mobile genetic elements. By understanding how the AAA+ ATPase regulator facilitates transposase recruitment and activation through DNA deformation and remodeling, researchers can potentially design inhibitors that disrupt this process. Targeting the interaction between IstB and IstA or interfering with the ATPase activity of IstB could serve as a promising strategy to inhibit transposase function, thereby preventing the dissemination of drug-resistance genes and toxins carried by mobile genetic elements. This mechanism provides a valuable target for the development of antimicrobial agents that can combat the spread of antibiotic resistance and virulence factors.

Could the DNA deformation and remodeling capabilities of AAA+ ATPase regulators be leveraged for applications in genome engineering or synthetic biology?

The DNA deformation and remodeling capabilities exhibited by AAA+ ATPase regulators, as demonstrated by IstB in the transposase activation mechanism, hold significant potential for applications in genome engineering and synthetic biology. Leveraging the ability of AAA+ ATPase regulators to manipulate DNA structure could enable precise control over gene expression, DNA repair, and genome editing processes. By harnessing the DNA remodeling properties of these regulators, researchers could design novel tools for targeted gene insertion, deletion, or modification in various organisms. Additionally, the insights gained from studying the transposase activation mechanism could inspire the development of synthetic biological systems that utilize AAA+ ATPase regulators to orchestrate complex DNA rearrangements for biotechnological applications. This highlights the versatility of AAA+ ATPase regulators in genome engineering and synthetic biology endeavors.