Publication: Insertion behavior of the Bacillus thuringiensis Cry4Ba insecticidal protein into lipid monolayers
Issued Date
2005-10-15
Resource Type
ISSN
10960384
00039861
00039861
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2-s2.0-26844482932
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Mahidol University
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SCOPUS
Bibliographic Citation
Archives of Biochemistry and Biophysics. Vol.442, No.2 (2005), 180-186
Suggested Citation
Yodsoi Kanintronkul, Toemsak Srikhirin, Chanan Angsuthanasombat, Teerakiat Kerdcharoen Insertion behavior of the Bacillus thuringiensis Cry4Ba insecticidal protein into lipid monolayers. Archives of Biochemistry and Biophysics. Vol.442, No.2 (2005), 180-186. doi:10.1016/j.abb.2005.08.005 Retrieved from: https://repository.li.mahidol.ac.th/handle/123456789/16284
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Title
Insertion behavior of the Bacillus thuringiensis Cry4Ba insecticidal protein into lipid monolayers
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Abstract
Toxicity mechanisms of Bacillus thuringiensis Cry insecticidal proteins involve membrane insertion and lytic pore formation in lipid bilayers of the target larval midgut cell membranes. The B. thuringiensis Cry4Ba mosquito-larvicidal protein has been shown to be capable of permeabilizing liposome vesicles and of forming ion channels in planar lipid bilayers. Here, the membrane interaction of the 65-kDa activated Cry4Ba protein with the lipid monolayers, comprising dipalmitoyl phosphatidylcholine, dioleoyl phosphatidylethanolamine, and cholesterol (Chol), was studied using Langmuir-Blodgett technique. The interactions of the Cry4Ba protein with the lipid monolayers were measured from the surface pressure versus area isotherms of the protein-lipid monolayers. The increase in the mean molecular area was demonstrated as an incorporation of the protein into lipid monolayers. The insertion of the Cry4Ba protein was monitored by measuring as an increase of the surface pressure at constant molecular area. For a given monolayer, the membrane insertion of the Cry4Ba reduced as the initial surface pressure increased. The Cry4Ba protein showed a strong preference of an insertion towards a Chol monolayer. In addition, the mixed monolayers of Chol showed an enhanced effect on the insertion kinetics of Cry4Ba into lipid films, suggesting its involvement in the modulation of the protein insertion. These findings provide the first evidence that the Cry4Ba protein is capable of inserting itself into lipid monolayers, depending on the packing density of the monolayers. Our results also indicate that only a limited part of the protein is likely to be involved in the insertion. © 2005 Elsevier Inc. All rights reserved.