Structure and Orientation Changes of ω- and γ-Gliadins at the Air−Water Interface:  A PM−IRRAS Spectroscopy and Brewster Angle Microscopy Study

Banc, Amélie; Desbat, Bernard; Renard, Denis; Popineau, Yves; Mangavel, Cécile; Navailles, Laurence

doi:10.1021/la702037k

Cited by 53 publications

(66 citation statements)

References 55 publications

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“…Furthermore, a band around 1454 cm –1 is observed. This band can be assigned to CN vibrations in proline residues (26–28) and is therefore consistent with the presence of 24 proline residues in MGD1 (~6%). At 20 h following protein injection, the intensity of amide I band slightly decreases and becomes more centered at 1635 cm –1 as assigned to β sheets.…”

Section: Resultssupporting

confidence: 83%

The influence of lipids on MGD1 membrane binding highlights novel mechanisms for galactolipid biosynthesis regulation in chloroplasts

et al. 2014

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Mono- and digalactosyldiacylglycerol (MGDG and DGDG) are the most abundant lipids of photosynthetic membranes (thylakoids). In Arabidopsis green tissues, MGD1 is the main enzyme synthesizing MGDG. This monotopic enzyme is embedded in the inner envelope membrane of chloroplasts. DGDG synthesis occurs in the outer envelope membrane. Although the suborganellar localization of MGD1 has been determined, it is still not known how the lipid/glycolipid composition influences its binding to the membrane. The existence of a topological relationship between MGD1 and "embryonic" thylakoids is also unknown. To investigate MGD1 membrane binding, we used a Langmuir membrane model allowing the tuning of both lipid composition and packing. Surprisingly, MGD1 presents a high affinity to MGDG, its product, which maintains the enzyme bound to the membrane. This positive feedback is consistent with the low level of diacylglycerol, the substrate of MGD1, in chloroplast membranes. By contrast, MGD1 is excluded from membranes highly enriched in, or made of, pure DGDG. DGDG therefore exerts a retrocontrol, which is effective on the overall synthesis of galactolipids. Previously identified activators, phosphatidic acid and phosphatidylglycerol, also play a role on MGD1 membrane binding via electrostatic interactions, compensating the exclusion triggered by DGDG. The opposite effects of MGDG and DGDG suggest a role of these lipids on the localization of MGD1 in specific domains. Consistently, MGDG induces the self-organization of MGD1 into elongated and reticulated nanostructures scaffolding the chloroplast membrane.-Sarkis, J., Rocha, J., Maniti, O., Jouhet, J., Vié, V., Block, M. A., Breton, C., Maréchal, E., Girard-Egrot, A. The influence of lipids on MGD1 membrane binding highlights novel mechanisms for galactolipid biosynthesis regulation in chloroplasts.

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Section: Resultssupporting

confidence: 83%

The influence of lipids on MGD1 membrane binding highlights novel mechanisms for galactolipid biosynthesis regulation in chloroplasts

et al. 2014

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“…IRRAS can be conducted at physiological temperature, at desired buffer and lipid compositions, and at low initial protein concentrations. IRRAS has previously been used to determine the orientation of short peptides in lipid monolayers (12-17), and secondary-structure changes of proteins upon ad- sorption to various interfaces (18)(19)(20)(21). Changes in the shape of IRRA bands were also used to postulate protein reorientations (22,23).…”

Section: Discussionmentioning

confidence: 99%

EHD2 restrains dynamics of caveolae by an ATP-dependent, membrane-bound, open conformation

Hoernke

Mohan

Larsson

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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The EH-domain-containing protein 2 (EHD2) is a dynamin-related ATPase that confines caveolae to the cell surface by restricting the scission and subsequent endocytosis of these membrane pits. For this, EHD2 is thought to first bind to the membrane, then to oligomerize, and finally to detach, in a stringently regulated mechanistic cycle. It is still unclear how ATP is used in this process and whether membrane binding is coupled to conformational changes in the protein. Here, we show that the regulatory N-terminal residues and the EH domain keep the EHD2 dimer in an autoinhibited conformation in solution. By significantly advancing the use of infrared reflection-absorption spectroscopy, we demonstrate that EHD2 adopts an open conformation by tilting the helical domains upon membrane binding. We show that ATP binding enables partial insertion of EHD2 into the membrane, where G-domain-mediated oligomerization occurs. ATP hydrolysis is related to detachment of EHD2 from the membrane. Finally, we demonstrate that the regulation of EHD2 oligomerization in a membrane-bound state is crucial to restrict caveolae dynamics in cells.EHD2 | caveolae | membrane-reshaping protein | membrane-bound protein structure | infrared reflection-absorption spectroscopy

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“…If the band appears as two components: one at the β-sheet position and another as a shoulder at 1682-1710 cm −1 it is indicative of an antiparallel β-sheet. The parallel β-sheet is predicted to have higher frequency for the lower component [62,64,65]. The disorder of random coils (unstructured) occurs at the same wavenumbers of the α-helices (1637-1650 cm −1 ), originating from the former broader and less intense bands compared to the α-helices [62,64,66].…”

Section: Pm-irrasmentioning

confidence: 99%

Interplay of mycolic acids, antimycobacterial compounds and pulmonary surfactant membrane: A biophysical approach to disease

Pinheiro

Giner‐Casares

Lúcio

et al. 2013

Biochimica et Biophysica Acta (BBA) - Biomembranes

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This work focuses on the interaction of mycolic acids (MAs) and two antimycobacterial compounds (Rifabutin and N'-acetyl-Rifabutin) at the pulmonary membrane level to convey a biophysical perspective of their role in disease. For this purpose, accurate biophysical techniques (Langmuir isotherms, Brewster angle microscopy, and polarization-modulation infrared reflection spectroscopy) and lipid model systems were used to mimic biomembranes: MAs mimic bacterial lipids of the Mycobacterium tuberculosis (MTb) membrane, whereas Curosurf® was used as the human pulmonary surfactant (PS) membrane model. The results obtained show that high quantities of MAs are responsible for significant changes on PS biophysical properties. At the dynamic inspiratory surface tension, high amounts of MAs decrease the order of the lipid monolayer, which appears to be a concentration dependent effect. These results suggest that the amount of MAs might play a critical role in the initial access of the bacteria to their targets. Both molecules also interact with the PS monolayer at the dynamic inspiratory surface. However, in the presence of higher amounts of MAs, both compounds improve the phospholipid packing and, therefore, the order of the lipid surfactant monolayer. In summary, this work discloses the putative protective effects of antimycobacterial compounds against the MAs induced biophysical impairment of PS lipid monolayers. These protective effects are most of the times overlooked, but can constitute an additional therapeutic value in the treatment of pulmonary tuberculosis (Tb) and may provide significant insights for the design of new and more efficient anti-Tb drugs based on their behavior as membrane ordering agents.

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Structure and Orientation Changes of ω- and γ-Gliadins at the Air−Water Interface: A PM−IRRAS Spectroscopy and Brewster Angle Microscopy Study

Cited by 53 publications

References 55 publications

The influence of lipids on MGD1 membrane binding highlights novel mechanisms for galactolipid biosynthesis regulation in chloroplasts

The influence of lipids on MGD1 membrane binding highlights novel mechanisms for galactolipid biosynthesis regulation in chloroplasts

EHD2 restrains dynamics of caveolae by an ATP-dependent, membrane-bound, open conformation

Interplay of mycolic acids, antimycobacterial compounds and pulmonary surfactant membrane: A biophysical approach to disease

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