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

Abstract

IS607-family transposons are unusual because they do not have terminal inverted repeats or generate target site duplications. They encode two protein-coding genes, but only tnpA is required for transposition. Our X-ray structures confirm that TnpA is a member of the serine recombinase (SR) family, but the chemically-inactive quaternary structure of the dimer, along with the N-terminal location of the DNA binding domain, are different from other SRs. TnpA dimers from IS1535 cooperatively associate with multiple subterminal repeats, which together with additional nonspecific binding, form a nucleoprotein filament on one transposon end that efficiently captures a second unbound end to generate the paired-end complex (PEC). Formation of the PEC does not require a change in the dimeric structure of the catalytic domain, but remodeling of the C-terminal α-helical region is involved. We posit that the PEC recruits a chemically-active conformer of TnpA to the transposon end to initiate DNA chemistry.

Occurrence and distribution characteristics of antibiotic resistance genes in sediments between urban and rural of the Liaohe River Basin, China

“…In short, tnpA-07 plays a key role in the co-occurrence network of macrolides and chloramphenicol resistance genes, and the connection point of the two large modules is tnpA-03. Previous studies have shown that MGEs, as the main promotion unit of horizontal transfer, play an important role in the occurrence and spread of ARGs (Chen et al, 2018, Zheng et al, 2018. In summary, the occurrence and spread of ARGs in sediments is highly correlated with MGEs, especially the tnpA gene plays a key role in the co-occurrence of ARGs.…”

“…SmartChip qPCR software was used to analyze the results, multiple peaks or wells whose ampli cation e ciency exceeded the range (90%-110%) were excluded and then screened for (1) A threshold cycle (CT) must be ≤31, (2) Positive samples must be repeated three times simultaneously. Calculate the relative copy number (Eq.1) was calculated based on previous studies (Chen et al, 2018). In addition, the method of comparing CT was also used to calculate the FC value of ARGs between the modi ed sample and the control (Eq.…”

Exaptation of inactivated host enzymes for structural roles in orthopoxviruses and novel protein folds revealed by protein structure modeling

“… C) OPG61 (F16L) (blue, aa 1-118 (of 231)) and best cellular Dali hit, the catalytic domain of a serin recombinase from Sulfolobus sp. L00 11 (archaea) (pdb 6dgc, (61) green, aa 65-164 (of 211)). Exemplified catalytic subdomain DRLXR (aa 139-143) in serin recombinase (magenta) and mutated stretch KQISI (aa 73-77) in OPG61 (cyan) are highlighted.…”

“… D) Structural alignment of prototype OPG61 (Q), 7 OPG members from diverse chordopoxviruses (blue, from top to bottom:MPXV Zaire 96-I-16, VACV, VARV, MCV subtype 1, SFV, MyxV and SORPV)) and three Dali hits (green, an integrase from Lactococcus phage TP901-1 (3bvp-B (62)), an IS607-like serine recombinase from Sulfolobus sp. L00 11 (6dgc-D (61)) and a resolvase family site-specific recombinase from Streptococcus pneumoniae SP19-BS75 (3guv-A (63)). Red bar highlights catalytic center (DRLxR motif) of serin recombinases.…”

Emergence of optrA-Mediated Linezolid Resistance in Enterococcus faecium: A Molecular Investigation in a Tertiary Hospital of Southwest China from 2014–2018

“…12 OptrA is often located on chromosomes or plasmids and can be transmitted by mobile genetic elements such as transposons and insertion sequences. [13][14][15] The most recently reported poxtA gene, mediating resistance to oxazolidinones, tetracyclines, and phenicols, was first described in an MRSA isolate from respiratory secretion of an Italian patient. 8 Since its first report, it has also been detected in isolates from animals and humans in many countries, including Italy, Greece, and China.…”