Multiple-bond kinetics from single-molecule pulling experiments: evidence for multiple NCAM bonds.

نویسندگان

  • E J Hukkanen
  • J A Wieland
  • A Gewirth
  • D E Leckband
  • R D Braatz
چکیده

The kinetic parameters of single bonds between neural cell adhesion molecules were determined from atomic force microscope measurements of the forced dissociation of the homophilic protein-protein bonds. The analytical approach described provides a systematic procedure for obtaining rupture kinetics for single protein bonds from bond breakage frequency distributions obtained from single-molecule pulling experiments. For these studies, we used the neural cell adhesion molecule (NCAM), which was recently shown to form two independent protein bonds. The analysis of the bond rupture data at different loading rates, using the single-bond full microscopic model, indicates that the breakage frequency distribution is most sensitive to the distance to the transition state and least sensitive to the molecular spring constant. The analysis of bond failure data, however, motivates the use of a double-bond microscopic model that requires an additional kinetic parameter. This double-bond microscopic model assumes two independent NCAM-NCAM bonds, and more accurately describes the breakage frequency distribution, particularly at high loading rates. This finding agrees with recent surface-force measurements, which showed that NCAM forms two spatially distinct bonds between opposed proteins.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Force distribution on multiple bonds controls the kinetics of adhesion in stretched cells.

We show herein how mechanical forces at macro or micro scales may affect the biological response at the nanoscale. The reason resides in the intimate link between chemistry and mechanics at the molecular level. These interactions occur under dynamic conditions such as the shear stress induced by flowing blood or the intracellular tension. Thus, resisting removal by mechanical forces, e.g., shea...

متن کامل

Mechanical distortion of protein receptor decreases the lifetime of a receptor-ligand bond.

Substantial experimental evidence indicates that the mechanical force applied to pull apart non-covalent molecular bonds (such as receptor-ligand pairs) can significantly decrease the bond lifetime. This evidence is often generated in single-molecule experiments that are designed to specifically test effects of pulling forces. However, the effect of compressive forces on the lifetime of recepto...

متن کامل

Kinetic Monte Carlo simulation of titin unfolding

Recently, it has become possible to unfold a single protein molecule titin, by pulling it with an atomic-force-microscope tip. In this paper, we propose and study a stochastic kinetic model of this unfolding process. Our model assumes that each immunoglobulin domain of titin is held together by six hydrogen bonds. The external force pulls on these bonds and lowers the energy barrier that preven...

متن کامل

Dwell time analysis of a single-molecule mechanochemical reaction.

Force-clamp spectroscopy is a novel technique for studying mechanochemistry at the single-bond level. Single disulfide bond reduction events are accurately detected as stepwise increases in the length of polyproteins that contain disulfide bonds and that are stretched at a constant force with the cantilever of an atomic force microscope (AFM). The kinetics of this reaction has been measured fro...

متن کامل

A Simple and Practical Spreadsheet-Based Method to Extract Single-Molecule Dissociation Kinetics from Variable Loading-Rate Force Spectroscopy Data.

A simple, practical, and model-free method is presented, by which kinetic data can be extracted from variable loading-rate single molecule dynamic force spectroscopy experiments. The constant sampling rate of digital acquisition facilitates the sorting of multiple force curves into histograms that reflect the collective force-time history of the bonds of interest. Combining the force-time histo...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Biophysical journal

دوره 89 5  شماره 

صفحات  -

تاریخ انتشار 2005