Co-translational protein targeting is an essential, evolutionarily conserved pathway for delivering nascent proteins to the proper cellular membrane. In this pathway, the signal recognition particle (SRP) first recognizes the N-terminal signal sequence of nascent proteins and subsequently interacts with the SRP receptor. For this, signal sequence binding in the SRP54 M domain must be effectively communicated to the SRP54 NG domain that interacts with the receptor. Here we present the 2.9 Å crystal structure of unbound- and signal sequence bound SRP forms, both present in the asymmetric unit. The structures provide evidence for a coupled binding and folding mechanism in which signal sequence binding induces the concerted folding of the GM linker helix, the finger loop, and the C-terminal alpha helix αM6. This mechanism allows for a high degree of structural adaptability of the binding site and suggests how signal sequence binding in the M domain is coupled to repositioning of the NG domain.
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http://dx.doi.org/10.1038/ncomms8163 | DOI Listing |
Mikrochim Acta
January 2025
Department of Chemistry and Biochemistry, National Chung Cheng University, 621301, Chia-Yi, Taiwan.
A fluorescent aptasensor was developed based on target-induced hairpin conformation switch coupled with nicking enzyme-assisted signal amplification (NESA) to detect the oligomeric form of ß-amyolid peptide (AβO) in cerebrospinal fluid. The hairpin DNA probe (HP) was specifically designed to recognize AβO. When AβO is present in the sensing system, it induces an HP conformational switch and triggers the NESA reaction.
View Article and Find Full Text PDFJ Phys Chem B
January 2025
Institute of Quantitative Biology, College of Life Sciences, and School of Physics, Zhejiang University, Hangzhou, Zhejiang 310058, China.
The emergence of nanopores in two-dimensional (2D) nanomaterials offers an attractive solid-state platform for high-throughput and low-cost DNA sequencing. However, several challenges remain to be addressed before their wide application, including the too-fast DNA translocation speed (compared to state-of-the-art single nucleoside detection techniques) and too large noise/signal ratios due to DNA fluctuations inside the nanopores. Here, we use molecular dynamics (MD) simulations to demonstrate the feasibility of utilizing RNA-DNA interactions in modulating DNA translocations in 2D MoS nanopores.
View Article and Find Full Text PDFbioRxiv
December 2024
Rutherford Appleton Laboratory, Research Complex at Harwell, Didcot, Oxfordshire, UK.
Conjugation, the major driver of the spread of antimicrobial resistance genes, relies on a conjugation pilus for DNA transfer. Conjugative pili, such as the F-pilus, are dynamic tubular structures, composed of a polymerized pilin, that mediate the initial donor-recipient interactions, a process known as mating pair formation (MPF). IncH are low-copy-number plasmids, traditionally considered broad host range, which are found in bacteria infecting both humans and animals.
View Article and Find Full Text PDFRecently, a novel African ancestry specific Parkinson's disease (PD) risk signal was identified at the gene encoding glucocerebrosidase ( ). This variant (rs3115534-G) is carried by ∼50% of West African PD cases and imparts a dose-dependent increase in risk for disease. The risk variant has varied frequencies across African ancestry groups, but is almost absent in European and Asian ancestry populations.
View Article and Find Full Text PDFHortic Res
January 2025
College of Horticulture, Shenyang Agricultural University, Shenyang 110866, China.
As one of the grave environmental hazards, soil salinization seriously limits crop productivity, growth, and development. When plants are exposed to salt stress, they suffer a sequence of damage mainly caused by osmotic stress, ion toxicity, and subsequently oxidative stress. As sessile organisms, plants have developed many physiological and biochemical strategies to mitigate the impact of salt stress.
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