On choosing a detergent for solution NMR studies of membrane proteins.
Translational diffusion coefficients and catalytic activities were measured for the integral membrane protein diacylglycerol kinase (DAGK) in a variety of types of detergent micelles. Despite the structural diversity of the detergents examined, the translational diffusion coefficients observed for DAGK spanned a fairly limited range of values: 2.7 to 4.7 (x10(-7) cm2/s). No general correlation was observed between the diffusion coefficients for the detergent-DAGK aggregates and the sizes of the corresponding protein-free micelles. These results indicate that the effective molecular weights of the DAGK-detergent aggregates were determined more by the structural properties of the protein than by the properties of the detergents. The catalytic activity of DAGK in detergents having medium-length alkyl chains such as dodecylphosphocholine or decylmaltoside was usually observed to be substantially higher than in short-chain detergents such as octylphosphocholine or octylglucoside. Taken together, the diffusion and activity results indicate that medium-chain detergents are generally preferred for use in NMR studies of complex membrane proteins because they are no worse than short-chained detergents in terms of increasing the effective molecular weight of the protein of interest while they are considerably better at maintaining native-like protein conformation. Among the 10 detergents examined, only sodium dodecylsulfate was observed to be unable to support DAGK activity under any conditions examined, suggest that this well-known protein denaturant should be used with care in studies of complex membrane proteins.
Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106-4970, USA.
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Vinogradova
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Sönnichsen
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Sanders
D003902:Detergents; D019852:Diacylglycerol Kinase / Q000737:chemistry / Q000378:metabolism; D004058:Diffusion; D004789:Enzyme Activation; D004795:Enzyme Stability; D008565:Membrane Proteins / Q000737:chemistry* / Q000378:metabolism; D008823:Micelles; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*
D003902:Detergents; D008565:Membrane Proteins; D008823:Micelles; D019852:Diacylglycerol Kinase