Specific antigen/antibody interactions measured by force microscopy

Dammer, Ulrich; Hegner, Martin; Anselmetti, Dario; Wagner, P.; Dreier, M; Huber, Walter; Güntherodt, H.‐J.

doi:10.1016/s0006-3495(96)79814-4

Cited by 430 publications

(326 citation statements)

References 16 publications

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“…We note that each of these measurements ended with the tether breaking at some maximum force or with a long un-recovered pause for >60 s, whereupon recording was stopped. The breakage of the tether could correspond to detachment of the DNA from the terminase-procapsid complex, unbinding of the DNA-terminase complex from the procapsid, or detachment of the procapsid from the antibody-coated microsphere; however, based on previous measurements of bond strengths of several different antibody-antigen pairs (which typically break within seconds under a 50-60 pN load) 27,28,29 , we suspect that the procapsid is detaching from the microsphere. Therefore, these measurements put a lower bound on the force-generating capability of the motor.…”

Section: The λ Dna Packaging Motor Generates High Forcesmentioning

confidence: 93%

Measurements of Single DNA Molecule Packaging Dynamics in Bacteriophage λ Reveal High Forces, High Motor Processivity, and Capsid Transformations

Fuller

Raymer

Rickgauer

et al. 2007

Journal of Molecular Biology

160

204

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Molecular motors drive genome packaging into preformed procapsids in many dsDNA viruses. Here, we present optical tweezers measurements of single DNA molecule packaging in bacteriophage λ. DNA-gpA-gpNu1 complexes were assembled with recombinant gpA and gpNu1 proteins and tethered to microspheres, and procapsids were attached to separate microspheres. DNA binding and initiation of packaging were observed within a few seconds of bringing these microspheres into proximity in the presence of ATP. The motor was observed to generate greater than 50 picoNewtons (pN) of force, in the same range as observed with bacteriophage ϕ29, suggesting that high force generation is a common property of viral packaging motors. However, at low capsid filling the packaging rate averaged ~600 bp/s, which is 3.5-fold higher than ϕ29, and the motor processivity was also 3-fold higher, with less than one slip per genome length translocated. The packaging rate slowed significantly with increasing capsid filling, indicating a buildup of internal force reaching 14 pN at 86% packaging, in good agreement with the force driving DNA ejection measured in osmotic pressure experiments and calculated theoretically. Taken together, these experiments show that the internal force that builds during packaging is largely available to drive subsequent DNA ejection. In addition, we observed an 80 bp/s dip in the average packaging rate at 30% packaging, suggesting that procapsid expansion occurs at this point following the buildup of an average of 4 pN of internal force. In experiments with a DNA construct longer than the wild-type genome, a sudden acceleration in packaging rate was observed above 90% packaging in many cases, and greater than 100% of the genome length was translocated, suggesting that internal force can rupture the immature procapsid.

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Section: The λ Dna Packaging Motor Generates High Forcesmentioning

confidence: 93%

Measurements of Single DNA Molecule Packaging Dynamics in Bacteriophage λ Reveal High Forces, High Motor Processivity, and Capsid Transformations

Fuller

Raymer

Rickgauer

et al. 2007

Journal of Molecular Biology

160

204

View full text Add to dashboard Cite

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“…Introduced to characterize interactions between receptor-ligand complexes (32,33) and complementary DNA strands (34), AFM-based single molecule force spectroscopy (SMFS) has been exploited to explore antibody-antigen recognition (35) and unfolding and refolding of soluble proteins (29,36) and to probe the adhesion of living cells at molecular resolution (37). Applied to membrane proteins, SMFS uses the AFM stylus to exert a mechanical pulling force to the terminal end of a protein that is embedded and anchored by the lipid membrane (see Fig.…”

mentioning

confidence: 99%

Substrate Binding Tunes Conformational Flexibility and Kinetic Stability of an Amino Acid Antiporter

Bippes

Zeltina

Casagrande

et al. 2009

Journal of Biological Chemistry

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We used single molecule dynamic force spectroscopy to unfold individual serine/threonine antiporters SteT from Bacillus subtilis. The unfolding force patterns revealed interactions and energy barriers that stabilized structural segments of SteT. Substrate binding did not establish strong localized interactions but appeared to be facilitated by the formation of weak interactions with several structural segments. Upon substrate binding, all energy barriers of the antiporter changed thereby describing the transition from brittle mechanical properties of SteT in the unbound state to structurally flexible conformations in the substrate-bound state. The lifetime of the unbound state was much shorter than that of the substrate-bound state. This leads to the conclusion that the unbound state of SteT shows a reduced conformational flexibility to facilitate specific substrate binding and a reduced kinetic stability to enable rapid switching to the bound state. In contrast, the bound state of SteT showed an increased conformational flexibility and kinetic stability such as required to enable transport of substrate across the cell membrane. This result supports the working model of antiporters in which alternate substrate access from one to the other membrane surface occurs in the substrate-bound state.

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“…More recent developments in AFM now allow the detection of molecular recognition events between single molecules using ligands attached to AFM tips for the recognition of receptors bound on rigid surfaces (12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25). By monitoring the cantilever def lection during approach-retraction cycles (i.e., forcevolume͞force-distance curves) at a constant (lateral) position on the sample, unbinding forces (i.e., the maximum force at the moment of receptor-ligand detachment) have been determined for various ligand-receptor pairs, including biotin-avidin (13,14,21), DNA bases (15), antibody-antigen (16)(17)(18)(19)(20)(21)(22), and cellrecognition proteins (23).…”

mentioning

confidence: 99%

“…By monitoring the cantilever def lection during approach-retraction cycles (i.e., forcevolume͞force-distance curves) at a constant (lateral) position on the sample, unbinding forces (i.e., the maximum force at the moment of receptor-ligand detachment) have been determined for various ligand-receptor pairs, including biotin-avidin (13,14,21), DNA bases (15), antibody-antigen (16)(17)(18)(19)(20)(21)(22), and cellrecognition proteins (23). This development has made it possible to use a single receptor molecule bound to the tip of an AFM cantilever to map the locations of ligands bound on solid surfaces (26).…”

mentioning

confidence: 99%

Combining constitutive materials modeling with atomic force microscopy to understand the mechanical properties of living cells

McElfresh

Baesu

Balhorn

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

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The goal of this work is to study the properties of living cells and cell membranes by using atomic force microscopy. During atomic force microscopy (AFM) measurement, there is a strong mechanical coupling between the AFM tip and the cell. The purpose of this paper is to present a model of the overall mechanical response of the cell that allows us to separate out the mechanical response of the cell from the local surface interactions we wish to quantify. These local interactions include recognition (or binding) events between molecules bound to an AFM tip (e.g., an antibody) and molecules or receptors on the cell surface (e.g., the respective antigen). The computational model differs from traditional Hertzian contact models by explicitly taking into account the mechanics of the biomembrane and cytoskeleton. The model also accounts for the mechanical response of the living cell during arbitrary deformation. The indentation of a bovine sperm cell is used to test the validity of this model, and further experiments are proposed to fully parameterize the model.

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Specific antigen/antibody interactions measured by force microscopy

Cited by 430 publications

References 16 publications

Measurements of Single DNA Molecule Packaging Dynamics in Bacteriophage λ Reveal High Forces, High Motor Processivity, and Capsid Transformations

Measurements of Single DNA Molecule Packaging Dynamics in Bacteriophage λ Reveal High Forces, High Motor Processivity, and Capsid Transformations

Substrate Binding Tunes Conformational Flexibility and Kinetic Stability of an Amino Acid Antiporter

Combining constitutive materials modeling with atomic force microscopy to understand the mechanical properties of living cells

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