Destabilizing mutations promote membrane protein misfolding.
In this work, the relationship between stability and propensity to misfold was probed for a series of purified variants of the polytopic integral membrane protein diacylglycerol kinase. It was observed that there was a strong correlation between stability and folding efficiency. The most common mutations that promoted misfolding were those which also destabilized the protein. These results imply that by targeting unstable membrane proteins for degradation, cellular protein folding quality control can eliminate proteins that have a high intrinsic propensity to misfold into aberrant structures. Moreover, the more rare class of amino acid mutations that promote misfolding without perturbing stability may be particularly dangerous because the mutant proteins may evade the surveillance of cellular quality control systems.
Nagy
Joanna K
JK
Department of Biochemistry and Center for Structural Biology, Vanderbilt University, Nashville, TN 37232-8725, USA.
Sanders
Charles R
CR
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution / Q000235:genetics; D003545:Cysteine / Q000235:genetics; D019852:Diacylglycerol Kinase / Q000737:chemistry* / Q000235:genetics*; D004795:Enzyme Stability / Q000235:genetics; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics; D014644:Genetic Variation; D019791:Guanidine / Q000737:chemistry; D007700:Kinetics; D008081:Liposomes; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics*; D008823:Micelles; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010713:Phosphatidylcholines / Q000737:chemistry; D011489:Protein Denaturation; D017510:Protein Folding; D013816:Thermodynamics
D029968:Escherichia coli Proteins; D008081:Liposomes; D008565:Membrane Proteins; D008823:Micelles; D010713:Phosphatidylcholines; D019852:Diacylglycerol Kinase; D019791:Guanidine; D003545:Cysteine; C028694:1-palmitoyl-2-oleoylphosphatidylcholine