2006 Canadian Society for Biochemistry, Molecular, and Cellular Biology
Niagara-on-the-Lake, Ontario, Canada; May 31-June 4, 2006.
Expression of Yeast Membrane Proteins in Yeast for Structure Determination
Mark E. Dumont
(Abstract): The challenge of overexpression and solubilization of eukaryotic integral membrane proteins is one of the most significant obstacles to structure determination of this important class of proteins. To identify properties of membrane proteins that may be predictive of successful overexpression, we analyzed expression levels of the genomic complement of over 1,000 predicted membrane proteins in a recently completed Saccharomyces cerevisiae protein expression library.
1 We detected statistically significant positive and negative correlations between high membrane protein expression and protein properties such as size, overall protein hydrophobicity, number of transmembrane helices, and amino acid composition of transmembrane segments. Expression levels of membrane and soluble proteins exhibited a nearly identical negative correlation with protein size and the overall hydrophobicity. However, high-level membrane protein expression was positively correlated with the hydrophobicity of predicted transmembrane segments. To further characterize yeast membrane proteins as potential targets for structure determination, we tested the solubility of 123 of the highest expressed yeast membrane proteins in six commonly used detergents. Over 75% of our test proteins could be classified into just four detergent solubility patterns. Protein size, number of transmembrane segments, and the hydrophobicity of predicted transmembrane segments all showed significant correlations with solubility in some detergents. These results suggest that bioinformatic approaches may be capable of identifying certain classes of membrane proteins most likely to be amenable to high level recombinant expression and efficient detergent solubilization, facilitating structural genomics approaches to membrane protein structure determination.
1 Gelperin DM, White MA, Wilkinson ML, Kon Y, Kung LA, Wise KJ, Lopez-Hoyo N, Jiang L,
Piccirillo S, Yu H, Gerstein M, Dumont ME, Phizicky EM, Snyder M, Grayhack EJ. (2005)
Biochemical and genetic analysis of the yeast proteome with a movable ORF collection.Genes
Dev. 19, 2816-2826.