prell lab fall 2016 presentation
TRANSCRIPT
Fall Quarter Overview
Grant Klausen Prell Lab
University of Oregon
Investigating Large Biological Complexes For Their Interactions and Structure
Using Native Mass For Investigating Biological Complexes
• Native mass spectrometry• High precision and
accuracy• Essentially unrestricted
mass range• Allows us to study both
mass and structure simultaneously
• Analyze multiple species in one spectrum
• Stoichiometry • Chemical identity
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Retaining Native Structure • ESI• Soft ionization technique
• Place protein of choice in specific volatile buffer• Spray it to retain its structure • Droplet of buffer evaporates• Kinetically trap protein
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Folded Unfolded
Our Instrument
Three S’s• Specificity • Selectivity• Sensitivity
Goal of the Lab: Studying Lipid Recruitment of Membrane Proteins Using Native Mass Spectrometry• Membrane proteins are
believed to associate with specific lipids• Potentially vital to assembly
and function of the protein• Determine native MS
techniques to study lipid recruitment• Other methods like X-ray
crystallography and Cryo-EM struggle with the heterogeneous nature of biolipids
Lipids have varying structures and charge properties• Zwitterionic• Negatively charged• Can adduct to basic sites
phosphocholine
phosphoethanolamine
cardiolipin
phosphoserine
sphingolipids
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Distinguishing Specific vs. Nonspecific Adduction
• Lipids readily adduct to proteins • In our case, non-membrane proteins and lipid head
groups
Easier to Unfold Protein than to Knock Adductions Off
Extent of Adduction for Acid Molecules Determined by Proton Affinity • Sodium and acid adduction are inversely related• Lower the charge state, more adductions seen • Less folded proteins result in more protonated
forms
Where We Are Headed• Effectively distinguishing between non-specific and
specific interactions• Testing full lipid adduction to non membrane
proteins • Develop approaches to prevent non-specific
adduction of lipids• Adding serine