Abstract
Small-angle neutron scattering (SANS) and dynamic light scattering (DLS) techniques have been applied to study the self-assembly processes of a microbially produced siderophore, marinobactin E (M E). M E is one of a series of marinobactins A-E that facilitate Fe(III) acquisition by the source bacterium through coordination of Fe(III) by the marinobactin headgroup. M E is a six-amino-acid peptide amphiphile appended by palmitic acid (C 16), and differs only in the nature of the fatty acid moiety from the other marinobactins. APO-M E (uncoordinated M E) assembles to form micelles with an average diameter of 4.0 nm. Upon coordination of one equivalent of Fe(III), the mean micellar diameter of Fe(III)-M E shrinks to ∼2.8 nm. However, in the presence of excess Fe(III), Fe(III)-M E undergoes a micelle-to-vesicle transition (MVT). At a small excess of Fe(III) over Fe(III)-M E (i.e., <1.2 Fe(III)/M E), a fraction of the Fe(III)-M E micelles rearrange into ∼200 nm diameter unilamellar vesicles. At even greater Fe(III)/M E ratios (e.g., 2-3) multilamellar aggregates begin to emerge, consistent with either multilamellar vesicles or lamellar stacks. The MVT exhibited by M E may represent a unique mechanism by which marine bacteria may detect and sequester iron required for growth.
Original language | English (US) |
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Pages (from-to) | 12109-12114 |
Number of pages | 6 |
Journal | Langmuir |
Volume | 21 |
Issue number | 26 |
DOIs | |
State | Published - Dec 20 2005 |
Externally published | Yes |
ASJC Scopus subject areas
- General Materials Science
- Condensed Matter Physics
- Surfaces and Interfaces
- Spectroscopy
- Electrochemistry