This Article Full Text Full Text (PDF) Supplemental File All Versions of this Article: biophysj.104.045138v1 87/6/4007    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Ohta, S. Articles by Ikai, A. Search for Related Content PubMed PubMed Citation Articles by Ohta, S. Articles by Ikai, A.

Origin of Mechanical Strength of Bovine Carbonic Anhydrase Studied by Molecular Dynamics Simulation

Laboratory of Biodynamics, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Tokyo, Japan

Correspondence: Address reprint requests to Atsushi Ikai, E-mail: aikai{at}bio.titech.ac.jp.

The forced unfolding process of bovine carbonic anhydrase II (BCA II) was examined at the atomic level by the molecular dynamics (MD) simulation. By force spectroscopy, experimentally obtained force-extension curves (F-E curves) showed a prominent force peak after 50 nm extension. F-E curves obtained from our simulation had three force peaks appearing after extensions of 10–17 nm, 40 nm, and 53 nm, each signifying a brittle fracture of a specific local structure. Upon undergoing the final fracture at 53 nm of extension, the entire molecule became a single flexible chain and was further extended to its full theoretical length, almost as a random coil. This feature of the 53-nm peak strongly suggested its close correspondence to the experimentally observed force peak at 60-nm extension. The 53-nm peak in the molecular dynamics simulation corresponded to the unfolding process of the ß-sheeted core that includes zinc-coordinating histidine residues. These results suggest that the structural change occurring at 50–60 nm in atomic force microscopy experiments corresponded to the destruction of the zinc coordination site.

This article has been cited by other articles:

				S. Safarian, M. Saffarzadeh, S. J. Zargar, and A. A. Moosavi-Movahedi Molten Globule-Like State of Bovine Carbonic Anhydrase in the Presence of Acetonitrile J. Biochem., June 1, 2006; 139(6): 1025 - 1033. [Abstract] [Full Text] [PDF]