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1rkk
From Proteopedia
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[[Image:1rkk.gif|left|200px]] | [[Image:1rkk.gif|left|200px]] | ||
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'''POLYPHEMUSIN I NMR SOLUTION STRUCTURE''' | '''POLYPHEMUSIN I NMR SOLUTION STRUCTURE''' | ||
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==About this Structure== | ==About this Structure== | ||
| - | + | Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1RKK OCA]. | |
==Reference== | ==Reference== | ||
Structure-activity relationships for the beta-hairpin cationic antimicrobial peptide polyphemusin I., Powers JP, Rozek A, Hancock RE, Biochim Biophys Acta. 2004 May 6;1698(2):239-50. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/15134657 15134657] | Structure-activity relationships for the beta-hairpin cationic antimicrobial peptide polyphemusin I., Powers JP, Rozek A, Hancock RE, Biochim Biophys Acta. 2004 May 6;1698(2):239-50. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/15134657 15134657] | ||
| - | [[Category: Protein complex]] | ||
[[Category: Hancock, R E.W.]] | [[Category: Hancock, R E.W.]] | ||
[[Category: Powers, J P.S.]] | [[Category: Powers, J P.S.]] | ||
[[Category: Rozek, A.]] | [[Category: Rozek, A.]] | ||
| - | [[Category: | + | [[Category: Anti-microbial peptide]] |
| - | [[Category: | + | [[Category: Beta hairpin]] |
| - | [[Category: | + | [[Category: Disulfide bridge]] |
| - | [[Category: | + | [[Category: Polyphemusin]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 07:36:38 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 04:36, 3 May 2008
POLYPHEMUSIN I NMR SOLUTION STRUCTURE
Overview
The solution structure of polyphemusin I was determined using (1)H-NMR spectroscopy. Polyphemusin I was found to be an amphipathic, beta-hairpin connected by a type I' beta-turn. The 17 low-energy structures aligned very well over the beta-sheet region while both termini were poorly defined due in part to a hinge-like region centred in the molecule about arginine residues 6 and 16. Conversely, a linear analogue, PM1-S, with all cysteines simultaneously replaced with serine was found to be dynamic in nature, and a lack of medium and long-range NOEs indicated that this molecule displayed no favoured conformation. Circular dichroism (CD) spectroscopy confirmed that in solution, 50% trifluoroethanol (TFE) and in the presence of liposomes, PM1-S remained unstructured. The antimicrobial activity of PM1-S was found to be 4- to 16-fold less than that of polyphemusin I and corresponded with a 4-fold reduction in bacterial membrane depolarization. Both peptides were able to associate with lipid bilayers in a similar fashion; however, PM1-S was completely unable to translocate model membranes while polyphemusin I retained this activity. It was concluded that the disulfide-constrained, beta-sheet structure of polyphemusin I is required for maximum antimicrobial activity. Disruption of this structure results in reduced antimicrobial activity and completely abolishes membrane translocation indicating that the linear PM1-S acts through a different antimicrobial mechanism.
About this Structure
Full crystallographic information is available from OCA.
Reference
Structure-activity relationships for the beta-hairpin cationic antimicrobial peptide polyphemusin I., Powers JP, Rozek A, Hancock RE, Biochim Biophys Acta. 2004 May 6;1698(2):239-50. PMID:15134657 Page seeded by OCA on Sat May 3 07:36:38 2008
