title: Lysophospholipid micelles sustain the stability and catalytic activity of diacylglycerol kinase in the absence of lipids.
abstract: There has been a renewal of interest in interactions of membrane proteins with detergents and lipids, sparked both by recent results that illuminate the structural details of these interactions and also by the realization that some experimental membrane protein structures are distorted by detergent-protein interactions. The integral membrane enzyme diacylglycerol kinase (DAGK) has long been thought to require the presence of lipid as an obligate "cofactor" in order to be catalytically viable in micelles. Here, we report that near-optimal catalytic properties are observed for DAGK in micelles composed of lysomyristoylphosphatidylcholine (LMPC), with significant activity also being observed in micelles composed of lysomyristoylphosphatidylglycerol and tetradecylphosphocholine. All three of these detergents were also sustained high stability of the enzyme. NMR measurements revealed significant differences in DAGK-detergent interactions involving LMPC micelles versus micelles composed of dodecylphosphocholine. These results highlight the fact that some integral membrane proteins can maintain native-like properties in lipid-free detergent micelles and also suggest that C(14)-based detergents may be worthy of more widespread use in studies of membrane proteins.
authors.affiliation: Department of Biochemistry and Center for Structural Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-8725, USA.
authors.forename: Julia
authors.initials: J
authors.lastname: Koehler
authors.forename: Endah S
authors.initials: ES
authors.lastname: Sulistijo
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Sakakura
authors.forename: Hak Jun
authors.initials: HJ
authors.lastname: Kim
authors.forename: Charles D
authors.initials: CD
authors.lastname: Ellis
authors.forename: Charles R
authors.initials: CR
authors.lastname: Sanders
mesh_terms: D002942:Circular Dichroism; D019852:Diacylglycerol Kinase / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology*; D007700:Kinetics; D008244:Lysophosphatidylcholines / Q000378:metabolism; D008246:Lysophospholipids / Q000378:metabolism*; D008823:Micelles; D019906:Nuclear Magnetic Resonance, Biomolecular; D010715:Phosphatidylglycerols / Q000378:metabolism; D010767:Phosphorylcholine / Q000031:analogs & derivatives / Q000378:metabolism; D013696:Temperature
chemical_list: D008244:Lysophosphatidylcholines; D008246:Lysophospholipids; D008823:Micelles; D010715:Phosphatidylglycerols; C552372:lysomyristoylphosphatidylglycerol; D010767:Phosphorylcholine; C035255:myristoyllysophosphatidylcholine; C031166:n-tetradecylphosphorylcholine; D019852:Diacylglycerol Kinase