title: Med8, Med18, and Med20 subunits of the Mediator head domain are interdependent upon each other for folding and complex formation.
abstract: We have studied folding and complex formation of the yeast Mediator head-module protein subunits Med8, Med18, and Med20. Using a combination of immunoprecipitation, far-UV circular dichroism, and fluorescence measurements on recombinantly expressed and denatured proteins that were allowed to renature separately or in different combinations, we found that Med8, Med18, and Med20 can fold in different ways to form both soluble monomeric proteins and different distinct subcomplexes. However, the concurrent presence of all three protein subunits during the renaturation process is required for proper folding and trimer complex formation.
authors.affiliation: Department of Medical Biochemistry and Biophysics, Umeå University, SE-901 87 Umeå, Sweden.
authors.forename: David
authors.initials: D
authors.lastname: Adler
authors.forename: Hamidur
authors.initials: H
authors.lastname: Rahaman
authors.forename: Pernilla
authors.initials: P
authors.lastname: Wittung-Stafshede
authors.forename: Stefan
authors.initials: S
authors.lastname: Björklund
mesh_terms: D002942:Circular Dichroism; D056892:Mediator Complex / Q000737:chemistry* / Q000378:metabolism*; D008954:Models, Biological; D011485:Protein Binding / Q000187:drug effects; D011489:Protein Denaturation / Q000187:drug effects; D017510:Protein Folding / Q000187:drug effects; D055503:Protein Multimerization / Q000187:drug effects; D020673:Protein Renaturation / Q000187:drug effects; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000737:chemistry / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000378:metabolism*; D013329:Structure-Activity Relationship; D014508:Urea / Q000494:pharmacology
chemical_list: C421882:MED8 protein, S cerevisiae; D056892:Mediator Complex; D021122:Protein Subunits; C074748:SRB2 protein, S cerevisiae; C082149:SRB5 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014508:Urea