Mark D. Szczelkun
YOU?
Author Swipe
View article: Eco-evolutionary feedbacks drive the co-occurrence of restriction-modification systems and antimicrobial resistance genes
Eco-evolutionary feedbacks drive the co-occurrence of restriction-modification systems and antimicrobial resistance genes Open
Bacterial pathogens commonly become drug resistant via horizontal acquisition of antimicrobial resistance genes (ARGs), which are often encoded on mobile genetic elements (MGEs). Although bacterial defence systems are typically considered …
View article: Defence systems drive accessory genome interactions in <i>Pseudomonas aeruginosa</i>
Defence systems drive accessory genome interactions in <i>Pseudomonas aeruginosa</i> Open
As well as undergoing mutational selection, bacterial genomes are shaped by a complex evolutionary interplay among diverse accessory genome elements (AGEs). In this study we define AGEs as encompassing both autonomous elements including ph…
View article: Structure and Activation Mechanism of a Lamassu Phage Defence System
Structure and Activation Mechanism of a Lamassu Phage Defence System Open
Summary Lamassu is a diverse family of defence systems that protect bacteria, including pandemic strains of Vibrio cholerae , against phage infection. They target essential cellular processes, aborting infection and preventing phage propag…
View article: Various plasmid strategies limit the effect of bacterial restriction–modification systems against conjugation
Various plasmid strategies limit the effect of bacterial restriction–modification systems against conjugation Open
In bacteria, genes conferring antibiotic resistance are mostly carried on conjugative plasmids, mobile genetic elements that spread horizontally between bacterial hosts. Bacteria carry defence systems that defend them against genetic paras…
View article: The bacterial defense system MADS interacts with CRISPR-Cas to limit phage infection and escape
The bacterial defense system MADS interacts with CRISPR-Cas to limit phage infection and escape Open
The constant arms race between bacteria and their parasites has resulted in a large diversity of bacterial defenses, with many bacteria carrying multiple systems. Here, we report the discovery of a phylogenetically widespread defense syste…
View article: Various plasmid strategies limit the effect of bacterial Restriction-Modification systems against conjugation
Various plasmid strategies limit the effect of bacterial Restriction-Modification systems against conjugation Open
In bacteria, genes conferring antibiotic resistance are mostly carried on conjugative plasmids, mobile genetic elements which spread horizontally between bacterial hosts. Bacteria carry defence systems which defend them against genetic par…
View article: Short-range translocation by a restriction enzyme motor triggers diffusion along DNA
Short-range translocation by a restriction enzyme motor triggers diffusion along DNA Open
Cleavage of bacteriophage DNA by the Type III restriction-modification enzymes requires long-range interaction between DNA sites. This is facilitated by one-dimensional diffusion (‘DNA sliding’) initiated by ATP hydrolysis catalyzed by a s…
View article: Short-range DNA translocation initiates long-range 1-dimensional DNA diffusion by the Type III restriction enzyme EcoP15I
Short-range DNA translocation initiates long-range 1-dimensional DNA diffusion by the Type III restriction enzyme EcoP15I Open
Cleavage of bacteriophage DNA by the Type III Restriction-Modification enzymes requires long-range interaction between DNA sites. This is facilitated by 1-dimensional diffusion (“DNA sliding”) initiated by ATP hydrolysis catalysed by a sup…
View article: Bacteriostatic antibiotics promote CRISPR-Cas adaptive immunity by enabling increased spacer acquisition
Bacteriostatic antibiotics promote CRISPR-Cas adaptive immunity by enabling increased spacer acquisition Open
Phages impose strong selection on bacteria to evolve resistance against viral predation. Bacteria can rapidly evolve phage resistance via receptor mutation or using their CRISPR-Cas adaptive immune systems. Acquisition of CRISPR immunity r…
View article: ENDO-Pore: high-throughput linked-end mapping of single DNA cleavage events using nanopore sequencing
ENDO-Pore: high-throughput linked-end mapping of single DNA cleavage events using nanopore sequencing Open
Mapping the precise position of DNA cleavage events plays a key role in determining the mechanism and function of endonucleases. ENDO-Pore is a high-throughput nanopore-based method that allows the time resolved mapping single molecule DNA…
View article: ENDO-Pore: High-throughput linked-end mapping of single DNA cleavage events using nanopore sequencing
ENDO-Pore: High-throughput linked-end mapping of single DNA cleavage events using nanopore sequencing Open
Mapping the precise position of DNA cleavage events plays a key role in determining the mechanism and function of endonucleases. ENDO-Pore is a high-throughput nanopore-based method that allows the time resolved mapping single molecule DNA…
View article: A gate and clamp regulate sequential DNA strand cleavage by CRISPR-Cas12a
A gate and clamp regulate sequential DNA strand cleavage by CRISPR-Cas12a Open
CRISPR-Cas12a has been widely used for genome editing and diagnostic applications, yet it is not fully understood how RNA-guided DNA recognition activates the sequential cleavage of the non-target strand (NTS) followed by the target strand…
View article: Bacteriostatic antibiotics promote the evolution of CRISPR-Cas immunity
Bacteriostatic antibiotics promote the evolution of CRISPR-Cas immunity Open
Phage therapy can be used in combination with antibiotics to combat infections with bacterial pathogens 1–3 . However, bacteria can rapidly evolve phage resistance via receptor mutation, or using their CRISPR-Cas adaptive immune systems 4 …
View article: Mitochondrial import, health and mtDNA copy number variability seen when using type II and type V CRISPR effectors
Mitochondrial import, health and mtDNA copy number variability seen when using type II and type V CRISPR effectors Open
Current methodologies for targeting the mitochondrial genome for research and/or therapy development in mitochondrial diseases are restricted by practical limitations and technical inflexibility. A molecular toolbox for CRISPR-mediated mit…
View article: 5′ modifications to CRISPR–Cas9 gRNA can change the dynamics and size of R-loops and inhibit DNA cleavage
5′ modifications to CRISPR–Cas9 gRNA can change the dynamics and size of R-loops and inhibit DNA cleavage Open
A key aim in exploiting CRISPR–Cas is gRNA engineering to introduce additional functionalities, ranging from individual nucleotide changes that increase efficiency of on-target binding to the inclusion of larger functional RNA aptamers or …
View article: 5’ modifications to CRISPR Cas9 gRNA can change the dynamics and size of R-loops and inhibit DNA cleavage
5’ modifications to CRISPR Cas9 gRNA can change the dynamics and size of R-loops and inhibit DNA cleavage Open
A key aim in exploiting CRISPR-Cas is the engineering of gRNA to introduce additional functionalities, ranging from small nucleotide changes that increase efficiency of on-target binding to the inclusion of large functional RNA aptamers an…
View article: Variability in mitochondrial import, mitochondrial health and mtDNA copy number using Type II and Type V CRISPR effectors
Variability in mitochondrial import, mitochondrial health and mtDNA copy number using Type II and Type V CRISPR effectors Open
Current methodologies for targeting the mitochondrial genome for basic research and/or therapeutic strategy development in mitochondrial diseases are restricted by practical limitations and technical inflexibility. The development of a fun…
View article: The Effect of DNA Topology on Observed Rates of R-Loop Formation and DNA Strand Cleavage by CRISPR Cas12a
The Effect of DNA Topology on Observed Rates of R-Loop Formation and DNA Strand Cleavage by CRISPR Cas12a Open
Here we explored the mechanism of R-loop formation and DNA cleavage by type V CRISPR Cas12a (formerly known as Cpf1). We first used a single-molecule magnetic tweezers (MT) assay to show that R-loop formation by Lachnospiraceae bacterium N…
View article: Hexameric assembly of the AAA+ protein McrB is necessary for GTPase activity
Hexameric assembly of the AAA+ protein McrB is necessary for GTPase activity Open
McrBC is one of the three modification-dependent restriction enzymes encoded by the Escherichia coli K12 chromosome. Amongst restriction enzymes, McrBC and its close homologues are unique in employing the AAA+ domain for GTP hydrolysis-dep…
View article: The H-subunit of the restriction endonuclease CglI contains a prototype DEAD-Z1 helicase-like motor
The H-subunit of the restriction endonuclease CglI contains a prototype DEAD-Z1 helicase-like motor Open
CglI is a restriction endonuclease from Corynebacterium glutamicum that forms a complex between: two R-subunits that have site specific-recognition and nuclease domains; and two H-subunits, with Superfamily 2 helicase-like DEAD domains, an…
View article: CgII cleaves DNA using a mechanism distinct from other ATP-dependent restriction endonucleases
CgII cleaves DNA using a mechanism distinct from other ATP-dependent restriction endonucleases Open
The restriction endonuclease CglI from Corynebacterium glutamicum recognizes an asymmetric 5'-GCCGC-3' site and cleaves the DNA 7 and 6/7 nucleotides downstream on the top and bottom DNA strands, respectively, in an NTP-hydrolysis dependen…
View article: Length heterogeneity at conserved sequence block 2 in human mitochondrial DNA acts as a rheostat for RNA polymerase POLRMT activity
Length heterogeneity at conserved sequence block 2 in human mitochondrial DNA acts as a rheostat for RNA polymerase POLRMT activity Open
The guanine (G)-tract of conserved sequence block 2 (CSB 2) in human mitochondrial DNA can result in transcription termination due to formation of a hybrid G-quadruplex between the nascent RNA and the nontemplate DNA strand. This structure…
View article: Structural insights into DNA sequence recognition by Type ISP restriction-modification enzymes
Structural insights into DNA sequence recognition by Type ISP restriction-modification enzymes Open
Engineering restriction enzymes with new sequence specificity has been an unaccomplished challenge, presumably because of the complexity of target recognition. Here we report detailed analyses of target recognition by Type ISP restriction-…