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Full-Text Articles in Life Sciences
Influence Of Single And Multiple Histidine Residues And Their Ionization Properties On Transmembrane Helix Dynamics, Orientations And Fraying, Fahmida Afrose
Influence Of Single And Multiple Histidine Residues And Their Ionization Properties On Transmembrane Helix Dynamics, Orientations And Fraying, Fahmida Afrose
Graduate Theses and Dissertations
Since aromatic and charged residues are often present in various locations of transmembrane helices of integral membrane proteins, their impacts on the molecular properties of transmembrane proteins and their interactions with lipids are of particular interest in many studies. In this work, I used solid-state deuterium NMR spectroscopy in designed model peptide GWALP23 [GGALW(LA)6LWLAGA] with selective deuterium labels to addresses the pH dependence and influence of single and multiple “guest” histidine residues in the orientation and dynamic behaviors of transmembrane proteins. The mutations include Gly to His (G2/22 to H2/22), Trp to His (W5/19 to H5/19) and Leu to His …
Investigations Of Protein-Lipid Interactions In Model Membranes: Influence Of Aromatic Anchoring Residues And Buried Polar Residues, Nick Gleason
Graduate Theses and Dissertations
To investigate in detail the interactions between transmembrane proteins and the lipid bilayers in which they are constituted, designed model peptides with selective isotopic labels were synthesized and analyzed by means of solid-state deuterium NMR spectroscopy. Starting from the well-characterized model peptide GWALP23, acetyl-GGALW(LA)6LWLAGA-amide, several Trp to Tyr mutations were compared to evaluate their respective interfacial anchoring abilities. It was found that Tyr, substituted on either or both termini, can effectively anchor the transmembrane alpha-helix, which then adopts a similar transmembrane topology in a range of bilayer thicknesses. Nevertheless, a consistent ~10° shift in tilt direction (helix rotation) is observed …
Protein-Lipid Interactions: Influence Of Anchoring Groups And Buried Arginine On The Properties Of Membrane-Spanning Peptides, Vitaly V. Vostrikov
Protein-Lipid Interactions: Influence Of Anchoring Groups And Buried Arginine On The Properties Of Membrane-Spanning Peptides, Vitaly V. Vostrikov
Graduate Theses and Dissertations
Designed transmembrane peptides were employed for investigations of protein-lipid interactions by means of oriented solid-state deuterium NMR spectroscopy using isotope-enriched alanine residues. Using the model GWALP23 sequence (GGALW(LA)6LWLAGA) as a host peptide having single interfacial tryptophan anchor residues, the effects of different guest mutations were explored. Replacements of glycine residues 2 and 22 to positively charged lysine or arginine on both termini had little influence on the peptide average orientation. Conversely, glycine to tryptophan substitutions had profound effects, manifested in the increased dynamics and altered tilt direction of the peptide. While the charged residues at the peptide termini did not …