Journal article
Folding kinetics of the outer membrane proteins OmpA and FomA into phospholipid bilayers
Publication Details
Authors: | Kleinschmidt, J. |
Publisher: | Elsevier |
Publication year: | 2006 |
Journal: | Chemistry and Physics of Lipids |
Pages range : | 30-47 |
Volume number: | 141 |
Issue number: | 1-2 |
ISSN: | 0009-3084 |
eISSN: | 1873-2941 |
DOI-Link der Erstveröffentlichung: |
Abstract
The folding mechanism of outer membrane proteins (OMPs) of Gram-negative bacteria into lipid bilayers has been studied using OmpA of E. coli and FomA of F. nucleatum as examples. Both, OmpA and FomA are soluble in unfolded form in urea and insert and fold into phospholipid bilayers upon strong dilution of the denaturant urea. OmpA is a structural protein and forms a small ion channel, composed of an 8-stranded transmembrane beta-barrel domain. FomA is a voltage-dependent porin, predicted to form a 14 stranded beta-barrel. Both OMPs fold into a range of model membranes of very different phospholipid compositions. Three membrane-bound folding intermediates of OmpA were discovered in folding studies with dioleoylphosphatidylcholine bilayers that demonstrated a highly synchronized mechanism of secondary and tertiary structure formation of beta-barrel membrane proteins. A study on FomA folding into lipid bilayers indicated the presence of parallel folding pathways for OMPs with larger transmembrane beta-barrels.
The folding mechanism of outer membrane proteins (OMPs) of Gram-negative bacteria into lipid bilayers has been studied using OmpA of E. coli and FomA of F. nucleatum as examples. Both, OmpA and FomA are soluble in unfolded form in urea and insert and fold into phospholipid bilayers upon strong dilution of the denaturant urea. OmpA is a structural protein and forms a small ion channel, composed of an 8-stranded transmembrane beta-barrel domain. FomA is a voltage-dependent porin, predicted to form a 14 stranded beta-barrel. Both OMPs fold into a range of model membranes of very different phospholipid compositions. Three membrane-bound folding intermediates of OmpA were discovered in folding studies with dioleoylphosphatidylcholine bilayers that demonstrated a highly synchronized mechanism of secondary and tertiary structure formation of beta-barrel membrane proteins. A study on FomA folding into lipid bilayers indicated the presence of parallel folding pathways for OMPs with larger transmembrane beta-barrels.
Keywords
149024-69-1 (OMPA outer membrane proteins, Bacterial Outer Membrane Proteins, Bacterial Outer Membrane Proteins/chemistry/metabolism, Escherichia coli Proteins, Escherichia coli Proteins/chemistry/metabolism, Kinetics, Lipid Bilayers, Lipid Bilayers, Lipid Bilayers/chemistry/metabolism, Membrane Proteins, Membrane Proteins/chemistry/metabolism, Phosphatidylcholines, Phosphatidylcholines/chemistry/metabolism, Phospholipids, Phospholipids/chemistry/metabolism, Porins, Porins/chemistry/metabolism, Protein Folding
