Kinetics of the M‐Intermediate in the Photocycle of Bacteriorhodopsin upon Chemical Modification with Surfactants

Chu, Li‐Kang; El‐Sayed, Mostafa A.

doi:10.1111/j.1751-1097.2009.00666.x

Cited by 10 publications

(8 citation statements)

References 52 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The functional behaviors of BR monomers are comparable in different nonionic surfactants, such as Triton X-100 and octylglucoside surfactants, 49 whereas ionic surfactants clearly influence the photocycle kinetics of oligomeric BR, in particular the deprotonation/reprotonation rates of the Schiff base. 55 We also observed that nonionic DDM and Brij-35 promoted similar photocycle behaviors for PR, yet TX100 and Zonyl surfactants modulated the photocycle kinetics of PR, albeit much more subtly versus the effects of oligomerization. Differences in the effects of TX100 on PR and BR function are especially interesting, considering that TX100 promotes monomer formation for both proteins.…”

Section: ■ Results and Discussionsupporting

confidence: 53%

“…Although only a limited number of studies interrogate the role of surfactants in BR function, their observations are mostly consistent with those of our studies of PR. The functional behaviors of BR monomers are comparable in different nonionic surfactants, such as Triton X-100 and octylglucoside surfactants, whereas ionic surfactants clearly influence the photocycle kinetics of oligomeric BR, in particular the deprotonation/reprotonation rates of the Schiff base . We also observed that nonionic DDM and Brij-35 promoted similar photocycle behaviors for PR, yet TX100 and Zonyl surfactants modulated the photocycle kinetics of PR, albeit much more subtly versus the effects of oligomerization.…”

Section: Results and Discussionmentioning

confidence: 56%

See 1 more Smart Citation

Proteorhodopsin Function Is Primarily Mediated by Oligomerization in Different Micellar Surfactant Solutions

et al. 2019

View full text Add to dashboard Cite

The diverse functionalities of membrane proteins (MPs) have garnered much interest in leveraging these biomolecules for technological applications. One challenge of studying MPs in artificial micellar surfactant environments is that many factors modulate their structures and functionalities, including the surfactants that interact with the MP or their assembly into oligomers. As oligomerization offers a means by which MPs could selectively interact among the copious environmental factors in biological environments, we hypothesized that MP function is predominantly modified by oligomerization rather than interactions with local surfactants that, by comparison, largely interact with MPs nonspecifically. To test this, we study the light-activated proton pump proteorhodopsin (PR) in micellar surfactant solutions because it is functionally active in monomeric and oligomeric forms, the light-activated functionalities of which can be assessed in detail. The surfactant composition and oligomerization are correlated with PR function, as measured by the protonation behaviors of aspartic acid residue 97, which mediates light-activated proton transport, and the associated photocycle kinetics. The results demonstrate that oligomerization dominantly mediates PR function in different surfactant environments, whereas some surfactants can subtly modulate proton-pumping kinetics. This work underscores the importance of understanding and controlling oligomerization of MPs to study and exploit their function.

show abstract

Section: ■ Results and Discussionsupporting

confidence: 53%

Section: Results and Discussionmentioning

confidence: 56%

Proteorhodopsin Function Is Primarily Mediated by Oligomerization in Different Micellar Surfactant Solutions

et al. 2019

View full text Add to dashboard Cite

show abstract

“…The photoisomerization kinetics of the all- trans retinal in bR can be altered by the mutated residues at the retinal pocket, , monomerized configuration, delipidation of PM, and reconstituted forms in various membrane mimicking environments . The cascading thermodynamic photocycle kinetics at a given temperature can be influenced by the environmental acidity, presence of surfactants, − types of lipids in liposome to solubilize bR, and monomeric/trimeric configuration . bR can be solubilized in surfactants and liposomes, as well as incorporated in lipid nanodiscs.…”

Section: Introductionmentioning

confidence: 99%

Photochemistry of Bacteriorhodopsin with Various Oligomeric Statuses in Controlled Membrane Mimicking Environments: A Spectroscopic Study from Femtoseconds to Milliseconds

et al. 2019

Self Cite

View full text Add to dashboard Cite

Preparing transmembrane protein in controllable lipid bilayers is essential for unravelling the coupling of the environments and its dynamic functions. Monomerized bacteriorhodopsin (mbR) embedded in covalently circularized nanodiscs was prepared with dimyristoylphosphatidylglycerol (DMPG) lipid and circular membrane scaffold proteins of two different sizes, cE3D1 and cΔH5, respectively. The retinal photoisomerization kinetics and thermodynamic photocycle were examined by femtosecond and nanosecond transient absorption, respectively, covering the time scale from femtoseconds to hundreds of milliseconds. The kinetics of the retinal isomerization and proton migration from the protonated Schiff base to Asp-85 were not significantly different for monomeric bR solubilized in Triton X-100 or embedded in circularized nanodiscs. This can be ascribed to the local tertiary structures at the retinal pocket vicinity being similar among monomeric bR in various membrane mimicking environments. However, the aforementioned processes are intrinsically different for trimeric bR in purple membrane (PM) and delipidated PM. The reprotonation of the deprotonated Schiff base from Asp-96 in association with the decay of intermediate M, which involved wide-ranged structural alteration, manifested a difference in terms of the oligomeric statuses, as well as a slight dependence on the size of the nanodisc. In summary, bR oligomeric statuses, rather than the environmental factors, such as membrane mimicking systems and nanodisc size, play a significant role in bR photocycle associated with short-range processes, such as the retinal isomerization and deprotonation of protonated Schiff base at the retinal pocket. On the other hand, the environmental factors, such as the types of membrane mimicking systems and the size of nanodiscs, affect those dynamic processes involving wider structural alterations during the photocycle.

show abstract

“…50 In PM, the rise of intermediate M is slightly accelerated in the presence of cationic surfactants. 51 The rise of intermediate M will not be changed at low pH but will be retarded toward higher pH 9. 52 The generation of intermediate M is accelerated in the monomeric bR in Triton X-100 micelle, 53 whereas it is decelerated in the delipidated PM.…”

Section: Introductionmentioning

confidence: 98%

“…The cascading deprotonation of the protonated retinal Schiff base to Asp85 after the retinal photoisomerization is associated with the movement of the helix C, which enables the proton acceptor Asp85 to approach the protonated Schiff base . In PM, the rise of intermediate M is slightly accelerated in the presence of cationic surfactants . The rise of intermediate M will not be changed at low pH but will be retarded toward higher pH 9 .…”

Section: Introductionmentioning

confidence: 99%

Influence of Lipid Compositions in the Events of Retinal Schiff Base of Bacteriorhodopsin Embedded in Covalently Circularized Nanodiscs: Thermal Isomerization, Photoisomerization, and Deprotonation

et al. 2019

Self Cite

View full text Add to dashboard Cite

Covalently circularized nanodiscs using circular membrane scaffold protein (MSP) serve as a suitable membrane mimetic for transmembrane proteins by providing stability and tunability in lipid compositions, providing controllable biological environments for targeted proteins. In this work, monomeric bacteriorhodopsin (mbR) was embedded in lipid nanodiscs of different lipid compositions using negatively charged lipid dioleoyl phosphatidylglycerol (DOPG) and the zwitterion lipid dioleoyl phosphatidylcholine (DOPC), and the events associated with the retinal Schiff base, including the thermal isomerization during the dark adaptation, photoisomerization, and deprotonation, were investigated. The retinal thermal isomerization from all-trans, 15-anti to the 13-cis, 15-syn configuration during the dark adaptation was accelerated in the DOPG bilayer, whereas the processes in the DOPC bilayer and in Triton X-100 micelles were similar. This observation indicated that the negatively charged lipid reduced the barrier for retinal thermal isomerization at C13C14C15N in the ground electronic state. Furthermore, the broader absorption contour of mbR in the DOPC nanodisc probably indicated various retinal isomers in the light-adapted state, consistent with the observed nontwo-state dark adaptation kinetics. Moreover, the kinetics of the photoisomerization of the retinal was slightly decelerated upon increasing the content of DOPC. However, the cascading deprotonation of the protonated Schiff base is not dependent on the types of the surrounding lipids in the nanodiscs. In summary, our research deepens the understanding of the coupling between lipid membrane and the photochemistry of bR retinal Schiff base. Combined with the results of our previous works (Lee, T.-Y.; Yeh, V.; Chuang, J.; Chan, J. C. C.; Chu, L.-K.; Yu, T.-Y. Biophys. J. 2015, 109, 1899–1906; Kao, Y.-M.; Cheng, C.-H.; Syue, M.-L.; Huang, H.-Y.; Chen, I-C.; Yu, T.-Y.; Chu, L.-K. J. Phys. Chem. B 2019, 123, 2032–2039), these outcomes extend our understanding of the control of photochemistry and biophysical events for other photosynthetic proteins via altering the lipid environments.

show abstract

Kinetics of the M‐Intermediate in the Photocycle of Bacteriorhodopsin upon Chemical Modification with Surfactants

Cited by 10 publications

References 52 publications

Proteorhodopsin Function Is Primarily Mediated by Oligomerization in Different Micellar Surfactant Solutions

Proteorhodopsin Function Is Primarily Mediated by Oligomerization in Different Micellar Surfactant Solutions

Photochemistry of Bacteriorhodopsin with Various Oligomeric Statuses in Controlled Membrane Mimicking Environments: A Spectroscopic Study from Femtoseconds to Milliseconds

Influence of Lipid Compositions in the Events of Retinal Schiff Base of Bacteriorhodopsin Embedded in Covalently Circularized Nanodiscs: Thermal Isomerization, Photoisomerization, and Deprotonation

Contact Info

Product

Resources

About