Force spectra of single bacterial amyloid CsgA nanofibers

Lv, Jingqi; Li, Yingfeng; Guo, Pei; Liu, Yang; Ding, Ke; Li, Ké; Zhong, Chao; Xiao, Botao

doi:10.1039/d0ra02749a

Cited by 4 publications

(21 citation statements)

References 54 publications

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“…It is based on our previous study involving protein bers. 28 This method allows us to observe a wide scope of stretched structures with high precision without the need to build a complex functional surface. 19,20 Twist or torque may be further added to the tether as the magnets rotate.…”

Section: Discussionmentioning

confidence: 99%

“…Samples were then fixed with 8% glutaraldehyde and washed gently with pure water, as described in our previous report. 28 …”

Section: Methodsmentioning

confidence: 99%

“…Samples were then xed with 8% glutaraldehyde and washed gently with pure water, as described in our previous report. 28 The samples were dried in a desiccator. A Sputter Coater (Quorum) was used to coat a platinum lm onto the glass surfaces for 60 s in the vacuum.…”

Section: Scanning Electron Microscopymentioning

confidence: 99%

“…26,27 We previously described a method to "stick and scan" a protein nanober. 28 The ends of single nanobers were stuck to magnetic beads and a glass slide using a tag-free method. The stretched bers were xed and observed by SEM.…”

Section: Introductionmentioning

confidence: 99%

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Stick, stretch, and scan imaging method for DNA and filaments

Zeng

Gao

et al. 2021

RSC Adv.

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Section: Discussionmentioning

confidence: 99%

“…Samples were then fixed with 8% glutaraldehyde and washed gently with pure water, as described in our previous report. 28 …”

Section: Methodsmentioning

confidence: 99%

Section: Scanning Electron Microscopymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Stick, stretch, and scan imaging method for DNA and filaments

Zeng

Gao

et al. 2021

RSC Adv.

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“…Theoretical methods have been used to evaluate the mechanical unfolding and adhesion mechanism of a single CsgA protein and similar β-helix proteins. , This experiment used steer molecule dynamics (SMD) to obtain the complete dissipative work of the β-helix and its skeleton separation mechanism, which demonstrated its strong ductility . Additionally, several studies have been conducted on β-helix and β-helix-rich proteins. − While the mechanical properties of the entire CsgA fibers have been studied, , a few studies have assessed the mechanical properties of individual CsgA molecules.…”

Section: Introductionmentioning

confidence: 99%

Force Spectra of a Single CsgA Molecule and Amyloid Nanofibers Assembled from Chimeric Mfp5 and CBD Proteins: Implications for a Nanomaterial Testing Machine

Liu

et al. 2022

ACS Appl. Nano Mater.

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The CsgA protein in Escherichia coli can self-assemble into an amyloid nanofiber, making it a promising biomaterial capable of resisting harsh environments. The assembling and unfolding mechanism of a single CsgA molecule is essential for all applications of CsgA materials but remains poorly understood. CsgA-CBD and Mfp5-CsgA are chimeric proteins generated by introducing the chitin-binding domain (CBD) and mussel foot protein 5 (Mfp5) into CsgA. In this study, we used magnetic tweezers to study the mechanical properties of a single CsgA molecule and the CsgA-CBD and Mfp5-CsgA assembled nanofibers. Our results demonstrated that the unfolding spectra of five β-sheets of a single CsgA molecule were not uniform and that several β-sheets simultaneously broke after an external force was applied. We applied ∼331 kcal/mol of work, via mechanochemical coupling, to unfold CsgA to a 94.6% strain. The average persistence lengths of the CsgA-CBD and Mfp5-CsgA nanofibers were 2.7 and 4.5 nm, respectively, while Young’s moduli of the two nanofibers were 42.8 and 56.1 MPa, respectively, both of which were less than those of the CsgA nanofiber. A relatively high force was required to unfold some of the nanofibers, which indicated that mechanical stimuli could help remove amyloid particles. This study assesses the mechanical properties of a single CsgA and lays the foundation for its subsequent use as a biological material and provides new insights into mechanochemical coupling nanofibers to design materials with tunable functions.

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Fast and Reliable Electronic Assay of a Xylella fastidiosa Single Bacterium in Infected Plants Sap

et al. 2022

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Pathogens ultra-sensitive detection is vital for early diagnosis and provision of restraining actions and/or treatments. Among plant pathogens, Xylella fastidiosa is among the most threatening as it can infect hundreds of plant species worldwide with consequences on agriculture and the environment. An electrolyte-gated transistor is here demonstrated to detect X. fastidiosa at a limit-of-quantification (LOQ) of 2 ± 1 bacteria in 0.1 mL (20 colony-forming-unit per mL). The assay is carried out with a millimeter-wide gate functionalized with Xylella-capturing antibodies directly in saps recovered from naturally infected plants. The proposed platform is benchmarked against the quantitave polymerase chain reaction (qPCR) gold standard, whose LOQ turns out to be at least one order of magnitude higher. Furthermore, the assay selectivity is proven against the Paraburkholderia phytofirmans bacterium (negative-control experiment). The proposed label-free, fast (30 min), and precise (false-negatives, false-positives below 1%) electronic assay, lays the ground for an ultra-high performing immunometric point-of-care platform potentially enabling large-scale screening of asymptomatic plants.

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Force spectra of single bacterial amyloid CsgA nanofibers

Abstract: Magnetic tweezers were used to study the force spectra of CsgA, a major protein subunit of Escherichia coli biofilms, at fibril level.

Cited by 4 publications

References 54 publications

Stick, stretch, and scan imaging method for DNA and filaments

Stick, stretch, and scan imaging method for DNA and filaments

Force Spectra of a Single CsgA Molecule and Amyloid Nanofibers Assembled from Chimeric Mfp5 and CBD Proteins: Implications for a Nanomaterial Testing Machine

Fast and Reliable Electronic Assay of a Xylella fastidiosa Single Bacterium in Infected Plants Sap

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