Most well-known restriction endonucleases recognize palindromic DNA sequences and are classified as Type IIP. Due to the recognition and cleavage symmetry, Type IIP enzymes are usually found to act as homodimers in forming 2-fold symmetric enzyme-DNA complexes. Here we report an asymmetric complex of the Type IIP restriction enzyme MspI in complex with its cognate recognition sequence. Unlike any other Type IIP enzyme reported to date, an MspI monomer and not a dimer binds to a palindromic DNA sequence. The enzyme makes specific contacts with all 4 base pairs in the recognition sequence, by six direct and five water-mediated hydrogen bonds and numerous van der Waal contacts. This MspI-DNA structure represents the first example of asymmetric recognition of a palindromic DNA sequence by two different structural motifs in one polypeptide. A few possible pathways are discussed for MspI to cut both strands of DNA, either as a monomer or dimer.
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http://dx.doi.org/10.1016/j.str.2004.07.014 | DOI Listing |
Biosens Bioelectron
January 2025
School of Pharmacy, Jiangsu University, 212013, Zhenjiang, PR China. Electronic address:
To enhance the biomarker diagnostics sensitivity and selectivity of human papillomavirus type 16 oncoprotein E7 (HPV16 E7) in serum, a label/enzyme-free electrochemical detection platform was developed. This platform featured a type of "Super-turn-off" nanobiosensor monitored through differential pulse voltammetry (DPV). It integrated the magnetic self-assembly property of the α-FeO/FeO@Au/Sub/BSA signal transport nano-medium with the high specificity of CRISPR/Cas14a and the amplification capability of the bipedal walker (DNA walker composed of two ssDNA strands), resulting in the enhanced specificity and anti-interference performance while remaining stable at 4 °C for over 30 days.
View Article and Find Full Text PDFBiosci Microbiota Food Health
September 2024
Department of Agricultural Chemistry, Graduate School of Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan.
Although the clustered regularly interspaced short palindromic repeat (CRISPR)-Cas system has been extensively developed since its discovery for eukaryotic and prokaryotic genome editing and other genetic manipulations, there are still areas warranting improvement, especially regarding bacteria. In this study, BRD0539, a small-molecule inhibitor of Cas9 (SpCas9), was used to suppress the activity of the nuclease during genetic modification of , as well as to regulate CRISPR interference (CRISPRi). First, we developed and validated a CRISPR-SpCas9 system targeting the gene of .
View Article and Find Full Text PDFCRISPR J
January 2025
OceanOmics, The Minderoo Foundation, Perth, Australia.
Characterizing biodiversity using environmental DNA (eDNA) represents a paradigm shift in our capacity for biomonitoring complex environments, both aquatic and terrestrial. However, eDNA biomonitoring is limited by biases toward certain species and the low taxonomic resolution of current metabarcoding approaches. Shotgun metagenomics of eDNA enables the collection of whole ecosystem data by sequencing all molecules present, allowing characterization and identification.
View Article and Find Full Text PDFBioinform Adv
December 2024
Digital Technologies Research Center, National Research Council Canada, Ottawa, ON, K1A 0R6, Canada.
Motivation: Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-Cas9 system is a ground-breaking genome editing tool, which has revolutionized cell and gene therapies. One of the essential components involved in this system that ensures its success is the design of an optimal single-guide RNA (sgRNA) with high on-target cleavage efficiency and low off-target effects. This is challenging as many conditions need to be considered, and empirically testing every design is time-consuming and costly.
View Article and Find Full Text PDFFunct Plant Biol
January 2025
National Institute for Genomics and Advanced Biotechnology (NIGAB), NARC, Park Road, Islamabad 45500, Pakistan.
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