Publications de Halil Ibrahim Okur

Lysozyme Interaction with Phospholipid Nanodroplets Probed by Sum Frequency Scattering Vibrational Spectroscopy

Sylvie Roke, Jan Dedic, Halil Ibrahim Okur, Sergey Kulik

When a nanoparticle (NP) is introduced into a biological environment, its identity and interactions are immediately attributed to the dense layer of proteins that quickly covers the particle. The formation of this layer, dubbed the protein corona, is in ge ...

AMER CHEMICAL SOC2023

Ultrasensitive Label-Free Detection of Protein–Membrane Interaction Exemplified by Toxin-Liposome Insertion

Sylvie Roke, Matteo Dal Peraro, Chan Cao, Halil Ibrahim Okur, Mircea Ioan Iacovache, Tereza Schönfeldová

Measuring the high-affinity binding of proteins to liposome membranes remains a challenge. Here, we show an ultrasensitive and direct detection of protein binding to liposome membranes using high throughput second harmonic scattering (SHS). Perfringolysin ...

2022

Hyaluronan orders water molecules in its nanoscale extended hydration shells

Sylvie Roke, Jan Dedic, Halil Ibrahim Okur

Hyaluronan (HA) is an anionic, highly hydrated bio-polyelectrolyte found in the extracellular environment, like the synovial fluid between joints. We explore the extended hydration shell structure of HA in water using femto-second elastic second-harmonic s ...

AMER ASSOC ADVANCEMENT SCIENCE2021

Lipid Melting Transitions Involve Structural Redistribution of Interfacial Water

Sylvie Roke, Halil Ibrahim Okur, Filip Kovacik, Tereza Schönfeldová

Morphological and gel-to-liquid phase transitions of lipid membranes are generally considered to primarily depend on the structural motifs in the hydrophobic core of the bilayer. Structural changes in the aqueous headgroup phase are typically not considere ...

AMER CHEMICAL SOC2021

Transient domains of ordered water induced by divalent ions lead to lipid membrane curvature fluctuations

Sylvie Roke, Orly Bagunu Tarun, Halil Ibrahim Okur

Cations influence the electrostatic, chemical and mechanical properties of lipid bilayers. Here, label-free second harmonic microscopy shows that cation-induced transient ordering of water also plays a role in driving membrane curvature fluctuations, linki ...

NATURE PUBLISHING GROUP2020

Molecular Mechanism for the Interactions of Hofmeister Cations with Macromolecules in Aqueous Solution

Sylvie Roke, Halil Ibrahim Okur

Ion identity and concentration influence the solubility of macromolecules. To date, substantial effort has been focused on obtaining a molecular level understanding of specific effects for anions. By contrast, the role of cations has received significantly ...

AMER CHEMICAL SOC2020

On the stability and necessary electrophoretic mobility of bare oil nanodroplets in water

Sylvie Roke, Saranya Pullanchery Sankara Narayanan, Halil Ibrahim Okur, Hilton Barbosa De Aguiar, Sergey Kulik

Hydrophobic oil droplets, particles, and air bubbles can be dispersed in water as kinetically stabilized dispersions. It has been established since the 19th century that such objects harbor a negative electrostatic potential roughly twice larger than the t ...

AMER INST PHYSICS2020

Membrane–Protein–Hydration Interaction of α-Synuclein with Anionic Vesicles Probed via Angle-Resolved Second-Harmonic Scattering

Sylvie Roke, Jan Dedic, Halil Ibrahim Okur

Amyloid formation of the protein α-synuclein promotes neurodegeneration in Parkinson's disease. The normal function of α-synuclein includes synaptic vesicle transport and fusion, and the protein binds strongly to negatively charged vesicles in vitro. Here, ...

2019

Determination and evaluation of the nonadditivity in wetting of molecularly heterogeneous surfaces

Francesco Stellacci, Michele Ceriotti, Sylvie Roke, Quy Ong Khac, Halil Ibrahim Okur, David Mark Wilkins, Zhi Luo, Anna Murello, Filip Kovacik

The interface between water and folded proteins is very complex. Proteins have "patchy" solvent-accessible areas composed of domains of varying hydrophobicity. The textbook understanding is that these domains contribute additively to interfacial properties ...

National Academy of Sciences2019

Specific Ion Effects at the Interface of Nanometer-Sized Droplets in Water: Structure and Stability

Sylvie Roke, Halil Ibrahim Okur, Evangelia Zdrali

The interaction of ions with interfaces influences numerous processes in chemistry, physics, and biology, while different ion species behave differently at hydrophobic or hydrophilic interfaces. Despite its importance, ion specificity and its relation to s ...

2019