Nanomechanics of Protein-Based Biostructures

• Ikai Atsushi

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

抄録

In this article, we review recent studies on nanomechanics of biostructures performed in the Laboratory of Biodynamics at Tokyo Institute of Technology. We employed the force spectroscopy mode of the atomic force microscope, to determine the hidden mechanical properties of protein-based biostructures that have made life on the earth so successful. We investigated the mechanical heterogeneity of the internal structure of globular proteins and cell membranes. Single molecules of globular proteins were stretched from their two ends after being sandwiched between the probe of the atomic force microscope and the substrate through a covalent crosslinking system. The resulting force-extension curve revealed mechanical heterogeneities in the conformation of globular proteins. The covalent crosslinking system withstood a tensile force of up to 1.8±0.33 nN (loading rate = 11.7 nN/s) while most of the noncovalently folded protein sub-structures were completely stretched out with less force. The result of force spectroscopy supported a long-standing conjecture that an enzyme cannot simply be a soft material because it must catalyze chemical reactions involving the formation and breakdown of mechanically rigid covalent molecules. Next, the AFM force spectroscopy was applied to determine the force needed to disrupt noncovalently assembled biostructures such as composite biomembranes composed of lipids and proteins. We were able to show that intrinsic membrane proteins that are securely anchored to a lipid bilayer could be pulled out of the membrane with a significantly less force than that required for covalent bond breakdown, but with a force in the comparable range required for the disruption of the internal structures of globular proteins. From the available results from our group and other groups, a new concept of force-based biostructure assembly is emerging.

収録刊行物

• Japanese Journal of Applied Physics

  Japanese Journal of Applied Physics 43 (11A), 7365-7375, 2004

  The Japan Society of Applied Physics

キーワード

• atomic force microscopy (AFM)
• force spectroscopy
• protein stretching
• receptor mapping
• GroEL and protein interaction
• membrane protein extraction

詳細情報

• CRID: 1390282681241390720
• NII論文ID: 10014029610
• NII書誌ID: AA10457675
• DOI: 10.1143/jjap.43.7365
• ISSN: 13474065
• ISSN: 00214922
• NDL書誌ID: 7153962
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I7153962
• Web Site: http://stacks.iop.org/1347-4065/43/i=11R/a=7365/pdf
• 本文言語コード: en
• データソース種別:
  • JaLC
  • NDL
  • Crossref
  • CiNii Articles
  • KAKEN
• 抄録ライセンスフラグ: 使用不可