Two type I restriction enzymes from Salmonella species

1985 ◽  
Vol 182 (4) ◽  
pp. 579-587 ◽  
Author(s):  
Valakunja Nagaraja ◽  
John C.W. Shepherd ◽  
Therese Pripfl ◽  
Thomas A. Bickle
Keyword(s):  
Restriction Enzymes ◽  
Type I

scholarly journals Type I Restriction Systems: Sophisticated Molecular Machines (a Legacy of Bertani and Weigle)

2000 ◽  
Vol 64 (2) ◽  
pp. 412-434 ◽  
Author(s):  
Noreen E. Murray
Keyword(s):  
Genetic Manipulation ◽  
Molecular Motor ◽  
Restriction Enzymes ◽  
Target Sequence ◽  
Type I ◽  
Dna Translocation ◽  
Chromosomal Dna ◽  
Dna Breakage ◽  
Intramolecular Communication ◽  
Alternative Activities

SUMMARY Restriction enzymes are well known as reagents widely used by molecular biologists for genetic manipulation and analysis, but these reagents represent only one class (type II) of a wider range of enzymes that recognize specific nucleotide sequences in DNA molecules and detect the provenance of the DNA on the basis of specific modifications to their target sequence. Type I restriction and modification (R-M) systems are complex; a single multifunctional enzyme can respond to the modification state of its target sequence with the alternative activities of modification or restriction. In the absence of DNA modification, a type I R-M enzyme behaves like a molecular motor, translocating vast stretches of DNA towards itself before eventually breaking the DNA molecule. These sophisticated enzymes are the focus of this review, which will emphasize those aspects that give insights into more general problems of molecular and microbial biology. Current molecular experiments explore target recognition, intramolecular communication, and enzyme activities, including DNA translocation. Type I R-M systems are notable for their ability to evolve new specificities, even in laboratory cultures. This observation raises the important question of how bacteria protect their chromosomes from destruction by newly acquired restriction specifities. Recent experiments demonstrate proteolytic mechanisms by which cells avoid DNA breakage by a type I R-M system whenever their chromosomal DNA acquires unmodified target sequences. Finally, the review will reflect the present impact of genomic sequences on a field that has previously derived information almost exclusively from the analysis of bacteria commonly studied in the laboratory.

scholarly journals DNA translocation blockage, a general mechanism of cleavage site selection by type I restriction enzymes

1999 ◽  
Vol 18 (9) ◽  
pp. 2638-2647 ◽  
Author(s):  
Pavel Janscak ◽  
Maria P. MacWilliams ◽  
Ursula Sandmeier ◽  
Valakunja Nagaraja ◽  
Thomas A. Bickle
Keyword(s):  
Site Selection ◽  
Cleavage Site ◽  
Restriction Enzymes ◽  
General Mechanism ◽  
Type I ◽  
Dna Translocation

scholarly journals Type I restriction enzymes and their relatives

2013 ◽  
Vol 42 (1) ◽  
pp. 20-44 ◽  
Author(s):  
W. A. M. Loenen ◽  
D. T. F. Dryden ◽  
E. A. Raleigh ◽  
G. G. Wilson
Keyword(s):  
Restriction Enzymes ◽  
Type I

scholarly journals Phylogenomics, Epigenomics, Virulome, and Mobilome of Gram-negative Bacteria Co-resistant to Carbapenems and Polymyxins: A One-Health Systematic Review and Meta-analyses

2021 ◽  
Author(s):  
Winnie Thabisa Ramaloko ◽  
John Osei Sekyere
Keyword(s):  
Bacterial Infections ◽  
One Health ◽  
Phylogenetic Analyses ◽  
Restriction Enzymes ◽  
Type I ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
E Coli ◽  
Meta Analyses ◽  
Restriction Modification

Gram-negative bacteria (GNB) continue to develop resistance against important antibiotics including last-resort ones such as carbapenems and polymyxins. An analysis of GNB with co-resistance to carbapenems and polymyxins from a One Health perspective is presented. Data of species name, country, source of isolation, resistance genes (ARGs), plasmid type, clones, and mobile genetic elements (MGEs) were deduced from 129 articles from January 2016 to March 2021. Available genomes and plasmids were obtained from PATRIC and NCBI. Resistomes and methylomes were analysed using BAcWGSTdb and REBASE whilst Kaptive was used to predict capsule typing. Plasmids and other MEGs were identified using MGE Finder and ResFinder. Phylogenetic analyses were done using RAxML and annotated with MEGA 7. A total of 877 isolates, 32 genomes and 44 plasmid sequences were analysed. Most of these isolates were reported in Asian countries and were isolated from clinical, animal, and environmental sources. Colistin resistance was mostly mediated by mgrB inactivation, while OXA-48/181 was the most reported carbapenemase. IncX and IncI were the most common plasmids hosting carbapenemases and mcr genes. The isolates were co-resistant to other antibiotics, with floR (chloramphenicol) and fosA3 (fosfomycin) being common; E. coli ST156 and K. pneumoniae ST258 strains were common globally. Virulence genes and capsular KL-types were also detected. Type I, II, III and IV restriction modification systems were detected, comprising various MTases and restriction enzymes. The escalation of highly resistant isolates drains the economy due to untreatable bacterial infections, which leads to increasing global mortality rates and healthcare costs.

scholarly journals Impact of target site distribution for Type I restriction enzymes on the evolution of methicillin-resistant Staphylococcus aureus (MRSA) populations

2013 ◽  
Vol 41 (15) ◽  
pp. 7472-7484 ◽  
Author(s):  
Gareth A. Roberts ◽  
Patrick J. Houston ◽  
John H. White ◽  
Kai Chen ◽  
Augoustinos S. Stephanou ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Restriction Enzymes ◽  
Target Site ◽  
Type I ◽  
Methicillin Resistant ◽  
Site Distribution

Structural characterization of a modification subunit of a putative type I restriction enzyme fromVibrio vulnificusYJ016

2012 ◽  
Vol 68 (11) ◽  
pp. 1570-1577 ◽  
Author(s):  
Suk-Youl Park ◽  
Hyun-Ju Lee ◽  
Jung-Mi Song ◽  
Jiali Sun ◽  
Hyo-Jeong Hwang ◽  
...  
Keyword(s):  
Vibrio Vulnificus ◽  
Restriction Enzymes ◽  
Type I ◽  
Aromatic Rings ◽  
Recognition Sequence ◽  
Thermus Aquaticus ◽  
Methyl Group ◽  
Cofactor Binding ◽  
Adenine Ring ◽  
Adenine Base

In multifunctional type I restriction enzymes, active methyltransferases (MTases) are constituted of methylation (HsdM) and specificity (HsdS) subunits. In this study, the crystal structure of a putative HsdM subunit fromVibrio vulnificusYJ016 (vvHsdM) was elucidated at a resolution of 1.80 Å. A cofactor-binding site forS-adenosyl-L-methionine (SAM, a methyl-group donor) is formed within the C-terminal domain of an α/β-fold, in which a number of residues are conserved, including the GxGG and (N/D)PP(F/Y) motifs, which are likely to interact with several functional moieties of the SAM methyl-group donor. Comparison with the N6 DNA MTase ofThermus aquaticusand other HsdM structures suggests that two aromatic rings (Phe199 and Phe312) in the motifs that are conserved among the HsdMs may sandwich both sides of the adenine ring of the recognition sequence so that a conserved Asn residue (Asn309) can interact with the N6 atom of the target adenine base (a methyl-group acceptor) and locate the target adenine base close to the transferred SAM methyl group.

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