Serine Resolvases

Abstract

Serine resolvases are an interesting group of site-specific recombinases that, in their native contexts, resolve large fused replicons into smaller separated ones. Some resolvases are encoded by replicative transposons and resolve the transposition product, in which the donor and recipient molecules are fused, into separate replicons. Other resolvases are encoded by plasmids and function to resolve plasmid dimers into monomers. Both types are therefore involved in the spread and maintenance of antibiotic-resistance genes. Resolvases and the closely related invertases were the first serine recombinases to be studied in detail, and much of our understanding of the unusual strand exchange mechanism of serine recombinases is owed to those early studies. Resolvases and invertases have also served as paradigms for understanding how DNA topology can be harnessed to regulate enzyme activity. Finally, their relatively modular structure, combined with a wealth of structural and biochemical data, has made them good choices for engineering chimeric recombinases with designer specificity. This chapter focuses on the current understanding of serine resolvases, with a focus on the contributions of structural studies.

Single-Molecule Tethered Particle Motion: Stepwise Analyses of Site-Specific DNA Recombination

“…Conservative site-specific recombinases belong to two families, namely the serine and tyrosine families—the names indicating the active site nucleophiles utilized by members of each family for the strand cleavage step of recombination [ 39 , 40 , 52 , 53 , 54 ] ( Figure 2 and Figure 3 ). The catalytic serine or tyrosine forms a covalent bond with the phosphate group of the cleaved strand.…”

“…The subfamily of small serine recombinases, characterized by a small helix-turn-helix (HTH) DNA binding carboxyl-terminal domain, includes transposon- and plasmid-coded resolvases (resolvases of Tn3 and γδ transposons and Sin recombinase of staphylococcal plasmids, for example) and phage- or bacteria-coded invertases (Gin invertase of phage Mu and Hin invertase of Salmonella , for example). There is a wealth of biochemical, topological, and structural information on the mechanism of action of small serine recombinases [ 40 , 52 , 53 ]. In the subfamily of large serine recombinases, the carboxyl-terminal domain is considerably larger, 300 to 500 amino acids long.…”

Loop-closure Kinetics Reveal a Stable, Right-handed DNA Intermediate in Cre Recombination

“…Changes in DNA topology, manifested by properties such as supercoiling, knotting, and catenation, are integral to numerous cellular processes including DNA replication, transcription, and recombination. [1][2][3][4][5][6][7] Using circular DNA as a model system to investigate these processes allows associated topological changes to be readily characterized by established biophysical techniques such as gel electrophoresis. 8-10 2 However, making connections between changes in topological parameters and perturbations of canonical DNA geometry is not straightforward for several reasons.…”

“…This approach thus advances a more comprehensive dynamic analysis of large, biologically active nucleoprotein structures and their mechanisms. 5…”

Multiple serine transposase dimers assemble the transposon-end synaptic complex during IS607-family transposition

“…Serine recombinases (SRs) have been broadly classified into three subfamilies ( Smith and Thorpe, 2002 ). The small SRs (smSR) typically catalyze highly regulated recombination reactions between specific DNA sites that are usually on the same DNA molecule ( Johnson, 2015 ; Rice, 2015 ). The serine integrase or large SR (LSR) subfamily typically promote phage integration and excision between specific sites ( Smith, 2015 ; Van Duyne and Rutherford, 2013 ), but certain members promote DNA translocation reactions ( Bannam et al, 1995 ; Wang et al, 2006 ).…”