Berlin 2018 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 1: Protein Structure and Dynamics

BP 1.9: Vortrag

Montag, 12. März 2018, 12:00–12:15, H 1028

Protein assemblies of hGBP1 studied with Time Resolved-Small Angle Scattering — •Charlotte Lorenz and Andreas Stadler — Jülich Centre for Neutron Science (JCNS-1), Forschungszentrum Jülich

The human Guanylate Binding Protein 1 belongs to the family of dynamin-like proteins and is activated by addition of nucleotides which lead to protein oligomerization and stimulated GTPase activity. Standard protein expression and purification from bacterial E.coli cells leads to hGBP1 without the posttranslational attachment of farnesyl. With an integrative approach using analytical ultracentrifugation (AUC), dynamic light scattering (DLS) and on-line size exclusion chromatography (SEC-SAXS) we investigated intermediate states during the hydrolysis cycle of hGBP1. We were able to show that farnesylation prevents hGBP1 in the inactive monomeric form in nucleotide free solution, whereas the unmodified hGBP1 (nf-hGBP1) consists of monomers and dimers in nucleotide free solution. Furthermore, the nf-hGBP1 assembles to mostly dimers and tetramers after nucleotide induction. Contrary, the farnesylated hGBP1 assembles after nucleotide addition to large macromolecular structures. The polymer growth and composition is analyzed in solution using time resolved SAXS (TR-SAXS). This study shows the importance of posttranslational modifications regarding the signaling regulation and controlled growth of macromolecular complexes.