Molecular basis for transposase activation by a dedicated AAA+ ATPase

• Published in: Nature (London) 2024-06, Vol.630 (8018), p.1003-1011
• Main Authors: de la Gándara, Álvaro, Spínola-Amilibia, Mercedes, Araújo-Bazán, Lidia, Núñez-Ramírez, Rafael, Berger, James M., Arias-Palomo, Ernesto
• Format: Article
• Language: English
• Subjects: 14/28; 45; 45/29; 45/70; 631/337/2569; 631/535/1258/1259; 82; 82/16; 82/29; 82/80; 82/83; AAA Domain; Adenosine triphosphatase; Adenosine Triphosphatases - chemistry; Adenosine Triphosphatases - metabolism; Catalytic Domain; Chromosome rearrangements; CRISPR; Cryoelectron Microscopy; Deoxyribonucleic acid; DNA; DNA - chemistry; DNA - genetics; DNA - metabolism; DNA structure; DNA Transposable Elements - genetics; Electron microscopy; Enzyme Activation; Humanities and Social Sciences; Microscopy; Models, Molecular; multidisciplinary; Nucleic acids; Nucleotides; Protein Multimerization; Proteins; Science; Science (multidisciplinary); Substrates; Transcription activation; Transposase; Transposases - chemistry; Transposases - metabolism; Transposition
• ISSN: 0028-0836; 1476-4687; 1476-4687
• DOI: 10.1038/s41586-024-07550-6

Transposases drive chromosomal rearrangements and the dissemination of drug-resistance genes and toxins 1 – 3 . Although some transposases act alone, many rely on dedicated AAA+ ATPase subunits that regulate site selectivity and catalytic function through poorly understood mechanisms. Using IS 21 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. Specific interactions stimulate regulator ATPase activity and trigger a large conformational change on the transposase that positions the catalytic site to perform DNA strand transfer. These studies help explain how AAA+ ATPase regulators—which are used by classical transposition systems such as Tn7, Mu and CRISPR-associated elements—can remodel their substrate DNA and cognate transposases to promote function. Solution and cryogenic electron microscopy studies using IS 21 as a model transposase system show how AAA+ ATPases induce structural changes to prime target DNA and activate their associated transposases.