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| | {{STRUCTURE_1rkk| PDB=1rkk | SCENE= }} | | {{STRUCTURE_1rkk| PDB=1rkk | SCENE= }} |
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| - | '''POLYPHEMUSIN I NMR SOLUTION STRUCTURE'''
| + | ===POLYPHEMUSIN I NMR SOLUTION STRUCTURE=== |
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| - | ==Overview==
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| - | 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. | + | The line below this paragraph, {{ABSTRACT_PUBMED_15134657}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 15134657 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_15134657}} |
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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]. | + | Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1RKK OCA]. |
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| | ==Reference== | | ==Reference== |
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| | [[Category: Disulfide bridge]] | | [[Category: Disulfide bridge]] |
| | [[Category: Polyphemusin]] | | [[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 Mon Jul 28 18:52:32 2008'' |
Revision as of 15:52, 28 July 2008
Template:STRUCTURE 1rkk
POLYPHEMUSIN I NMR SOLUTION STRUCTURE
Template:ABSTRACT PUBMED 15134657
About this Structure
Full experimental 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 Mon Jul 28 18:52:32 2008
