Publication Date:
2001-02-07
Description:
Atomic force microscopy and single-molecule force spectroscopy were combined to image and manipulate purple membrane patches from Halobacterium salinarum. Individual bacteriorhodopsin molecules were first localized and then extracted from the membrane; the remaining vacancies were imaged again. Anchoring forces between 100 and 200 piconewtons for the different helices were found. Upon extraction, the helices were found to unfold. The force spectra revealed the individuality of the unfolding pathways. Helices G and F as well as helices E and D always unfolded pairwise, whereas helices B and C occasionally unfolded one after the other. Experiments with cleaved loops revealed the origin of the individuality: stabilization of helix B by neighboring helices.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Oesterhelt, F -- Oesterhelt, D -- Pfeiffer, M -- Engel, A -- Gaub, H E -- Muller, D J -- New York, N.Y. -- Science. 2000 Apr 7;288(5463):143-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉CeNS and Lehrstuhl fur angewandte Physik, Ludwig Maximilians-Universitat Munchen, Amalienstrasse 54, 80799 Munchen, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/10753119" target="_blank"〉PubMed〈/a〉
Keywords:
Amino Acid Sequence
;
Bacteriorhodopsins/*chemistry/genetics
;
Cysteine/chemistry
;
Halobacterium salinarum/*chemistry
;
Membrane Proteins/*chemistry/genetics
;
*Microscopy, Atomic Force
;
Models, Molecular
;
Molecular Sequence Data
;
Mutation
;
Protein Conformation
;
Protein Denaturation
;
*Protein Folding
;
Protein Structure, Secondary
;
Purple Membrane/*chemistry
;
Serine Endopeptidases/metabolism
;
Spectrum Analysis
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
Permalink
