title: In vitro assembly, purification, and crystallization of the rab geranylgeranyl transferase:substrate complex.
abstract: Posttranslational modification with the geranygeranyl moiety is essential for the ability of Rab GTPases to control processes of membrane docking and fusion. This modification is conferred by Rab geranylgeranyltransferase (RabGGTase), which catalyzes the transfer of two 20-carbon geranylgeranyl groups from geranylgeranyl pyrophosphate onto C-terminal cysteine residues of Rab proteins. The enzyme consists of a catalytic alpha/beta heterodimer and an accessory protein termed Rab escort protein (REP-1) that delivers the newly prenylated Rab proteins to their target membrane. In order to understand the structural basis of Rab prenylation, we have investigated in vitro assembly and crystallization of the RabGGTase:REP-1:Rab complex. In order to ensure maximal stability of the ternary complex, we generated its monoprenylated form, which corresponds to a reaction intermediate and displays the highest affinity between the components. This was achieved by expressing the individual components in baculovirus and Escherichia coli systems with subsequent purification followed by in vitro monoprenylation of Rab7 with immobilized recombinant RabGGTase. Purified monoprenylated REP-1:Rab7 was complexed with recombinant RabGGTase and crystallized in hanging drops. The crystals obtained initially diffract to 8 A on an in-house X-ray source.
authors.affiliation: Max-Plank-Institute for Molecular Physiology, Otto-Hahn-Strasse 11, Dortmund, 44227, Germany.
authors.forename: Alexey
authors.initials: A
authors.lastname: Rak
authors.forename: Anca
authors.initials: A
authors.lastname: Niculae
authors.forename: Alexandr
authors.initials: A
authors.lastname: Kalinin
authors.forename: Nicolas H
authors.initials: NH
authors.lastname: Thomä
authors.forename: Vadim
authors.initials: V
authors.lastname: Sidorovitch
authors.forename: Roger S
authors.initials: RS
authors.lastname: Goody
authors.forename: Kirill
authors.initials: K
authors.lastname: Alexandrov
mesh_terms: D019883:Alkyl and Aryl Transferases / Q000737:chemistry* / Q000302:isolation & purification*; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D003545:Cysteine / Q000737:chemistry; D004926:Escherichia coli / Q000378:metabolism; D005822:Genetic Vectors; D006801:Humans; D013058:Mass Spectrometry; D008954:Models, Biological; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D011994:Recombinant Proteins; D019883:Alkyl and Aryl Transferases; C075607:Rab geranylgeranyltransferase; D003545:Cysteine