Related Experiment Video
Updated: Jul 1, 2026
08:10
Molecular Spring Constant Analysis by Biomembrane Force Probe Spectroscopy
Published on: November 20, 2021
Exploring the Sulfatase 1 Catch Bond Free Energy Landscape using Jarzynski's Equality
Volker Walhorn1, Ann-Kristin Möller2, Christian Bartz3
1Experimental Biophysics and Applied Nanoscience, Faculty of Physics, Bielefeld University, Bielefeld, Germany. volker.walhorn@physik.uni-bielefeld.de.
Scientific Reports
|November 17, 2018
Summary
This study reveals catch bonds between human sulfatase 1 and heparan sulfate, characterized by two binding states. This finding advances understanding of molecular interactions and biological adhesion mechanisms.
Area of Science:
- Biochemistry
- Biophysics
- Molecular Biology
Background:
- Molecular bonds typically weaken under force (slip bonds).
- Catch bonds uniquely strengthen under force within a specific range.
- Few catch bond systems are identified, necessitating further investigation into their nature.
Purpose of the Study:
- To investigate the catch bond interaction between human sulfatase 1 hydrophilic domain (Sulf1HD) and heparan sulfate (HS).
- To characterize the thermodynamic and kinetic properties of the Sulf1HD/HS interaction.
- To elucidate the binding potential landscape and confirm the two-state binding model.
Main Methods:
- Atomic force microscopy-based single molecule force spectroscopy (AFM-SMFS).
- Application of Jarzynski's equality to estimate Gibbs free energy.
- Comprehensive thermodynamic and kinetic analysis.
Main Results:
- The Sulf1HD/HS interaction exhibits catch bond behavior.
- The binding potential landscape features two distinct potential wells, confirming a two-state binding model.
- A detailed picture of directed and processive heparan sulfate desulfation by Sulf1HD was established, despite a lack of structural data for Sulf1HD.
Conclusions:
- The Sulf1HD/HS interaction is a novel catch bond system.
- The two-state binding mechanism governs this interaction.
- This research provides insights into the functional mechanism of sulfatase 1 in heparan sulfate modification.
Related Concept Videos
02:39Gibbs Free Energy
One of the challenges of using the second law of thermodynamics to determine if a process is spontaneous is that it requires measurements of the entropy change for the system and the entropy change for the surroundings. An alternative approach involving a new thermodynamic property defined in terms of system properties only was introduced in the late nineteenth century by American mathematician Josiah Willard Gibbs. This new property is called the Gibbs free energy (G) (or simply the free...
02:49Calculating Standard Free Energy Changes
The free energy change for a reaction that occurs under the standard conditions of 1 bar pressure and at 298 K is called the standard free energy change. Since free energy is a state function, its value depends only on the conditions of the initial and final states of the system. A convenient and common approach to the calculation of free energy changes for physical and chemical reactions is by use of widely available compilations of standard state thermodynamic data. One method involves the...
02:56Free Energy and Equilibrium
The free energy change for a process may be viewed as a measure of its driving force. A negative value for ΔG represents a driving force for the process in the forward direction, while a positive value represents a driving force for the process in the reverse direction. When ΔGrxn is zero, the forward and reverse driving forces are equal, and the process occurs in both directions at the same rate (the system is at equilibrium).
Recall that Q is the numerical value of the mass action expression...
Recall that Q is the numerical value of the mass action expression...
02:23Gibbs Free Energy and Thermodynamic Favorability
The spontaneity of a process depends upon the temperature of the system. Phase transitions, for example, will proceed spontaneously in one direction or the other depending upon the temperature of the substance in question. Likewise, some chemical reactions can also exhibit temperature-dependent spontaneities. To illustrate this concept, the equation relating free energy change to the enthalpy and entropy changes for the process is considered:
02:13Bond Dissociation Energy and Activation Energy
Bond energy is the energy required to break a bond homolytically. These values are usually expressed in units of kcal/mol or kJ/mol and are referred to as bond dissociation energies when given for specific bonds or average bond energies when indicated for a given type of bond over many compounds. Firstly, the bond dissociation energy for a single bond is weaker than that of a double bond, which in turn is weaker than that of a triple bond. Secondly, hydrogen forms relatively strong bonds with...
00:55Free Energy and Equilibrium
The free energy change for a process may be viewed as a measure of its driving force. A negative value for ΔG represents a driving force for the process in the forward direction, while a positive value represents a driving force for the process in the reverse direction. When ΔG is zero, the forward and reverse driving forces are equal, and the process occurs in both directions at the same rate (the system is at equilibrium).
The reaction quotient, Q, is a convenient measure of the status of an...
The reaction quotient, Q, is a convenient measure of the status of an...