Specific Interactions of Mycosubtilin with Cholesterol-Containing Artificial Membranes

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• 作者：Mehmet Nail Nasir ; Franc抬oise Besson
• 刊名：Langmuir
• 出版年：2011
• 出版时间：September 6, 2011
• 年：2011
• 卷：27
• 期：17
• 页码：10785-10792
• 全文大小：984K
• 年卷期：v.27,no.17(September 6, 2011)
• ISSN：1520-5827

文摘

Mycosubtilin is a natural antimicrobial lipopeptide produced by Bacillus subtilis strains. It is characterized by its hemolytic and strong antifungal activities. Mycosubtilin interacts with the plasma membranes of sensitive cells. However, the molecular mechanisms of its biological activities have not been completely elucidated. Our purpose was therefore to analyze the interactions of mycosubtilin with biological membranes by using biomimetic membranes such as Langmuir monolayers and multilayers. Structural changes of mycosubtilin, involving its peptide backbone and the side chain of its tyrosyl residue, were observed when the lipopeptide was interacting with cholesterol-containing multilayers. The interactions of mycosubtilin with monolayers constituted by pure lipids and by phosholipid/cholesterol or phospholipid/sphingomyelin/cholesterol were also examined. An original behavior of mycosubtilin toward cholesterol-containing monolayers was found. However, this original behavior was lost when mycosubtilin was interacting with pure cholesterylacetate monolayers. This suggests the involvement of the alcohol group of cholesterol in mycosubtilin鈥揷holesterol interactions within membranes. Moreover, mycosubtilin induced changes in the organization and morphology of cholesterol-containing monolayers, and large condensed domains with different levels of condensation appeared only in the case of DPPC/sphingomyelin/cholesterol monolayer.