1
|
Umegawa Y, Kato S, Seo S, Shinoda W, Kawatake S, Matsuoka S, Murata M. Protein-lipid acyl chain interactions: Depth-dependent changes of segmental mobility of phospholipid in contact with bacteriorhodopsin. Biophys Chem 2024; 308:107204. [PMID: 38412762 DOI: 10.1016/j.bpc.2024.107204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2023] [Revised: 01/31/2024] [Accepted: 02/20/2024] [Indexed: 02/29/2024]
Abstract
Boundary lipids surrounding membrane proteins play an essential role in protein function and structure. These protein-lipid interactions are mainly divided into electrostatic interactions between the polar amino acids of proteins and polar heads of phospholipids, and hydrophobic interactions between protein transmembrane sites and phospholipid acyl chains. Our previous report (Kawatake et al., Biochim. Biophys. Acta 1858 [2016] 2106-2115) covered a method for selectively analyzing boundary lipid interactions and showed differences in membrane protein-peripheral lipid interactions due to differences in their head group. Interactions in the hydrophobic acyl chains of phospholipids are relatively consistent among proteins, but the details of these interactions have not been elucidated. In this study, we reconstituted bacteriorhodopsin as a model protein into phospholipid membranes labeled with 2H and 13C for solid-state NMR measurement to investigate the depth-dependent effect of the head group structure on the lipid bilayer. The results showed that the position of the phospholipid near the carbonyl carbon was affected by the head group in terms of selectivity for protein surfaces, whereas in the deep interior of the bilayer near the leaflet interface, there was little difference between the head groups, indicating that the dependence of their interactions on the head group was much reduced.
Collapse
Affiliation(s)
- Yuichi Umegawa
- JST-ERATO, Lipid Active Structure Project, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; Forefront Research Center, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan.
| | - Sho Kato
- JST-ERATO, Lipid Active Structure Project, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Sangjae Seo
- Department of Materials Chemistry, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan; Division of Supercomputing, Korea Institute of Science and Technology Information, 245 Daehak-ro, Yuseong-gu, Daejeon 34141, South Korea
| | - Wataru Shinoda
- Department of Materials Chemistry, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan; Research Institute for Interdisciplinary Science, Okayama University, 3-1-1, Tsushima-naka, Okayama 700-8530, Japan
| | - Satoshi Kawatake
- JST-ERATO, Lipid Active Structure Project, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; Forefront Research Center, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Shigeru Matsuoka
- JST-ERATO, Lipid Active Structure Project, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; Forefront Research Center, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Michio Murata
- JST-ERATO, Lipid Active Structure Project, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| |
Collapse
|
2
|
Archaeal Lipids Regulating the Trimeric Structure Dynamics of Bacteriorhodopsin for Efficient Proton Release and Uptake. Int J Mol Sci 2022; 23:ijms23136913. [PMID: 35805918 PMCID: PMC9278134 DOI: 10.3390/ijms23136913] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 06/19/2022] [Accepted: 06/20/2022] [Indexed: 11/30/2022] Open
Abstract
S-TGA-1 and PGP-Me are native archaeal lipids associated with the bacteriorhodopsin (bR) trimer and contribute to protein stabilization and native dynamics for proton transfer. However, little is known about the underlying molecular mechanism of how these lipids regulate bR trimerization and efficient photocycling. Here, we explored the specific binding of S-TGA-1 and PGP-Me with the bR trimer and elucidated how specific interactions modulate the bR trimeric structure and proton release and uptake using long-term atomistic molecular dynamic simulations. Our results showed that S-TGA-1 and PGP-Me are essential for stabilizing the bR trimer and maintaining the coherent conformational dynamics necessary for proton transfer. The specific binding of S-TGA-1 with W80 and K129 regulates proton release on the extracellular surface by forming a “Glu-shared” model. The interaction of PGP-Me with K40 ensures proton uptake by accommodating the conformation of the helices to recruit enough water molecules on the cytoplasmic side. The present study results could fill in the theoretical gaps of studies on the functional role of archaeal lipids and could provide a reference for other membrane proteins containing similar archaeal lipids.
Collapse
|
3
|
Inada M, Kinoshita M, Matsumori N. Archaeal Glycolipid S-TGA-1 Is Crucial for Trimer Formation and Photocycle Activity of Bacteriorhodopsin. ACS Chem Biol 2020; 15:197-204. [PMID: 31647217 DOI: 10.1021/acschembio.9b00756] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Although it has been demonstrated that membrane proteins (MPs) require lipids to ensure their structural and functional integrity, details on how lipid-MP interactions regulate MPs are still unclear. Recently, we developed a concise method for quantitatively evaluating lipid-MP interactions and applied it to bacteriorhodopsin (bR), a halobacterial MP that forms trimers and acts as a light-driven proton pump. Consequently, we found that the halobacterial glycolipid, S-TGA-1, has the highest affinity for bR, among other lipids. In this study, we examined the effects of S-TGA-1 on bR via visible circular dichroism spectroscopy, flash photolysis, and proton influx measurement. The results showed that S-TGA-1 efficiently promotes trimer formation, photocycle, and proton pumping in bR. Our data also suggested that the bR photocycle is restored as a consequence of the trimerization induced by the lipid. This study demonstrates clearly that lipids specifically interacting with MPs can have significant impacts on MP structure and/or function. The methodology adopted in our studies can be applied to other MPs and will help elucidate the physiological functions of lipids in terms of lipid-MP interactions, thus accelerating "lipid chemical biology" studies.
Collapse
Affiliation(s)
- Masataka Inada
- Department of Chemistry, Graduate School of Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Masanao Kinoshita
- Department of Chemistry, Graduate School of Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Nobuaki Matsumori
- Department of Chemistry, Graduate School of Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| |
Collapse
|
4
|
Yamagami M, Tsuchikawa H, Cui J, Umegawa Y, Miyazaki Y, Seo S, Shinoda W, Murata M. Average Conformation of Branched Chain Lipid PGP-Me That Accounts for the Thermal Stability and High-Salinity Resistance of Archaeal Membranes. Biochemistry 2019; 58:3869-3879. [DOI: 10.1021/acs.biochem.9b00469] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Masaki Yamagami
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
- JST ERATO, Lipid Active Structure Project, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Hiroshi Tsuchikawa
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Jin Cui
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
- JST ERATO, Lipid Active Structure Project, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Yuichi Umegawa
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
- JST ERATO, Lipid Active Structure Project, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Yusuke Miyazaki
- Department of Materials Chemistry, Graduate School of Engineering, Nagoya University, Nagoya 464-8603, Japan
| | - Sangjae Seo
- Department of Materials Chemistry, Graduate School of Engineering, Nagoya University, Nagoya 464-8603, Japan
| | - Wataru Shinoda
- Department of Materials Chemistry, Graduate School of Engineering, Nagoya University, Nagoya 464-8603, Japan
| | - Michio Murata
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
- JST ERATO, Lipid Active Structure Project, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| |
Collapse
|
5
|
Lazarova T, Mlynarczyk K, Querol E, Tenchov B, Filipek S, Padrós E. Identification of Specific Effect of Chloride on the Spectral Properties and Structural Stability of Multiple Extracellular Glutamic Acid Mutants of Bacteriorhodopsin. PLoS One 2016; 11:e0162952. [PMID: 27657718 PMCID: PMC5033488 DOI: 10.1371/journal.pone.0162952] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 08/31/2016] [Indexed: 11/18/2022] Open
Abstract
In the present work we combine spectroscopic, DSC and computational approaches to examine the multiple extracellular Glu mutants E204Q/E194Q, E204Q/E194Q/E9Q and E204Q/E194Q/E9Q/E74Q of bacteriorhodopsin by varying solvent ionic strength and composition. Absorption spectroscopy data reveal that the absorption maxima of multiple EC Glu mutants can be tuned by the chloride concentration in the solution. Visible Circular dichroism spectra imply that the specific binding of Cl- can modulate weakened exciton chromophore coupling and reestablish wild type-like bilobe spectral features of the mutants. The DSC data display reappearance of the reversible thermal transition, higher Tm of denaturation and an increase in the enthalpy of unfolding of the mutants in 1 M KCl solutions. Molecular dynamics simulations indicate high affinity binding of Cl- to Arg82 and to Gln204 and Gln194 residues in the mutants. Analysis of the experimental data suggests that simultaneous elimination of the negatively charged side chain of Glu194 and Glu204 is the major cause for mutants' alterations. Specific Cl- binding efficiently coordinates distorted hydrogen bonding interactions of the EC region and reconstitutes the conformation and structure stability of mutated bR in WT-like fashion.
Collapse
Affiliation(s)
- Tzvetana Lazarova
- Unitat de Biofísica, Departament de Bioquímica i de Biologia Molecular, Facultat de Medicina, and Centre d'Estudis en Biofísica, Universitat Autònoma de Barcelona, Barcelona, Spain
- * E-mail: (TL); (EP)
| | - Krzysztof Mlynarczyk
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, Warsaw, Poland
| | - Enric Querol
- Institut de Biomedicina i Biotecnologia, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Boris Tenchov
- Department of Medical Physics and Biophysics, Faculty of Medicine, Medical University – Sofia, Sofia, Bulgaria
| | - Slawomir Filipek
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, Warsaw, Poland
| | - Esteve Padrós
- Unitat de Biofísica, Departament de Bioquímica i de Biologia Molecular, Facultat de Medicina, and Centre d'Estudis en Biofísica, Universitat Autònoma de Barcelona, Barcelona, Spain
- * E-mail: (TL); (EP)
| |
Collapse
|
6
|
Cui J, Kawatake S, Umegawa Y, Lethu S, Yamagami M, Matsuoka S, Sato F, Matsumori N, Murata M. Stereoselective synthesis of the head group of archaeal phospholipid PGP-Me to investigate bacteriorhodopsin–lipid interactions. Org Biomol Chem 2015; 13:10279-84. [DOI: 10.1039/c5ob01252j] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Phosphatidylglycerophosphate methyl ester (PGP-Me), a major constituent of the archaeal purple membrane, is essential for the proper proton-pump activity of bacteriorhodopsin (bR).
Collapse
Affiliation(s)
- Jin Cui
- Department of Chemistry
- Osaka University
- Toyonaka
- Japan
- JST ERATO
| | | | - Yuichi Umegawa
- Department of Chemistry
- Osaka University
- Toyonaka
- Japan
- JST ERATO
| | - Sébastien Lethu
- Department of Chemistry
- Osaka University
- Toyonaka
- Japan
- JST ERATO
| | | | | | - Fuminori Sato
- JST ERATO
- Lipid Active Structure Project
- Osaka University
- Toyonaka
- Japan
| | | | - Michio Murata
- Department of Chemistry
- Osaka University
- Toyonaka
- Japan
- JST ERATO
| |
Collapse
|
7
|
Patra TK, Singh JK. Polymer directed aggregation and dispersion of anisotropic nanoparticles. SOFT MATTER 2014; 10:1823-1830. [PMID: 24652389 DOI: 10.1039/c3sm52216d] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The aggregation and dispersion of two anisotropic nanoparticles (NPs), cubes and tetrahedrons, in a polymer matrix are studied in this work using coarse-grained molecular dynamics simulations. We present the phase diagrams of NP-polymer composites, depicting microscopically phase-separated, dispersed, and bridged cubes and tetrahedrons in a polymer matrix, which depend on the interaction between the NPs and polymer (εnp), along with the NPs' volume fraction (ϕ). The microscopic phase separation occurs at very low εnp, where NPs self-organize into multidimensional structures, depending on ϕ. In particular, for tetrahedrons, a cross-over from an ordered spherical aggregate to a disordered sheet-like aggregate is observed with increasing ϕ. In the case of cubes, a transition from cubic array → square column → square array (sheet) is identified with increasing ϕ. The clusters of NPs are characterized by their asphericity and principal radii of gyration. The free energy profile for a structured assembly is estimated, which clearly shows that the successful assembly of NPs is energetically favorable at a lower temperature. However, there exists an energy barrier for the successful assembly of all the NPs in the system. At intermediate εnp, a transition from a clustered state to a state comprising dispersed cubes and tetrahedrons in a polymer matrix is observed. At higher εnp, a further transition takes place, where gas-like dispersed NPs form a liquid-like aggregate via polymer layers. Therefore, the findings in this work illustrate that the effective interaction between anisotropic NPs in a polymer matrix is very diverse, which can generate multidimensional structured assemblies, with the disordered clustering, dispersion, and bridging-induced aggregation of NPs.
Collapse
Affiliation(s)
- Tarak K Patra
- Department of Chemical Engineering, Indian Institute of Technology Kanpur, Kanpur-208016, India.
| | | |
Collapse
|
8
|
Ming M, Wang Y, Wu J, Ma D, Li Q, Ding J. Triton X-100 can alter the temporal sequence of the light-driven proton pump of archaerhodopsin 4. FEBS Lett 2006; 580:6749-53. [PMID: 17134701 DOI: 10.1016/j.febslet.2006.11.035] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2006] [Revised: 10/30/2006] [Accepted: 11/13/2006] [Indexed: 11/18/2022]
Abstract
We report that Triton X-100 can alter the temporal sequence of the light-induced proton uptake and release of archaerhodopsin 4 (AR4), a proton pumping protein in a species of Halobacteria from a Tibetan salt lake. Under physiological conditions, AR4 isolated from the bacterium exhibits a reversed temporal order of proton release and uptake compared to what is observed for bacteriorhodopsin (BR). However, in the presence of Triton X-100 early proton release was observed in AR4 at neutral pH by us. Further, this temporal order for light-driven proton release and uptake for AR4 was found to be recovered after the removal of Triton X-100 by Biobeads. This phenomenon of detergent-induced alteration of the order of proton release and uptake has not yet been reported in any other retinal-containing membrane protein such as BR. Our findings indicate that the function of AR4 is influenced by its self-assembled state, and meanwhile imply some subtle protein-lipid interactions or protein-protein interactions in adjusting the proton pumping behavior of AR4.
Collapse
Affiliation(s)
- Ming Ming
- Key Laboratory of Molecular Engineering of Polymers of the Chinese Ministry of Education, Department of Macromolecular Science, Lab of Advanced Materials, Fudan University, Shanghai 200433, China
| | | | | | | | | | | |
Collapse
|
9
|
Yamamoto K, Tuzi S, Saitô H, Kawamura I, Naito A. Conformation and dynamics changes of bacteriorhodopsin and its D85N mutant in the absence of 2D crystalline lattice as revealed by site-directed 13C NMR. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2006; 1758:181-9. [PMID: 16542636 DOI: 10.1016/j.bbamem.2006.01.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2005] [Revised: 01/05/2006] [Accepted: 01/31/2006] [Indexed: 11/16/2022]
Abstract
13C NMR spectra of [3-(13)C]Ala- and [1-(13)C]Val-labeled D85N mutant of bacteriorhodopsin (bR) reconstituted in egg PC or DMPC bilayers were recorded to gain insight into their secondary structures and dynamics. They were substantially suppressed as compared with those of 2D crystals, especially at the loops and several transmembrane alphaII-helices. Surprisingly, the 13C NMR spectra of [3-(13)C]Ala-D85N turned out to be very similar to those of [3-(13)C]Ala-bR in lipid bilayers, in spite of the presence of globular conformational and dynamics changes in the former as found from 2D crystalline preparations. No further spectral change was also noted between the ground (pH 7) and M-like state (pH 10) as far as D85N in lipid bilayers was examined, in spite of their distinct changes in the 2D crystalline state. This is mainly caused by that the resulting 13C NMR peaks which are sensitive to conformation and dynamics changes in the loops and several transmembrane alphaII-helices of the M-like state are suppressed already by fluctuation motions in the order of 10(4)-10(5) Hz interfered with frequencies of magic angle spinning or proton decoupling. However, 13C NMR signal from the cytoplasmic alpha-helix protruding from the membrane surface is not strongly influenced by 2D crystal or monomer. Deceptively simplified carbonyl 13C NMR signals of the loop and transmembrane alpha-helices followed by Pro residues in [1-(13)C]Val-labeled bR and D85N in 2D crystal are split into two peaks for reconstituted preparations in the absence of 2D crystalline lattice. Fortunately, 13C NMR spectral feature of reconstituted [1-(13)C]Val and [3-(13)C]Ala-labeled bR and D85N was recovered to yield characteristic feature of 2D crystalline form in gel-forming lipids achieved at lowered temperatures.
Collapse
Affiliation(s)
- Kazutoshi Yamamoto
- Department of Life Science, Himeji Institute of Technology, University of Hyogo, Harima Science Garden City 678-1297, Japan
| | | | | | | | | |
Collapse
|
10
|
Voïtchovsky K, Antoranz Contera S, Kamihira M, Watts A, Ryan JF. Differential stiffness and lipid mobility in the leaflets of purple membranes. Biophys J 2005; 90:2075-85. [PMID: 16387758 PMCID: PMC1386785 DOI: 10.1529/biophysj.105.072405] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Purple membranes (PM) are two-dimensional crystals formed by bacteriorhodopsin and a variety of lipids. The lipid composition and density in the cytoplasmic (CP) leaflet differ from those of the extracellular (EC) leaflet. A new way of differentiating the two sides of such asymmetric membranes using the phase signal in alternate contact atomic force microscopy is presented. This method does not require molecular resolution and is applied to study the stiffness and intertrimer lipid mobility in both leaflets of the PM independently over a broad range of pH and salt concentrations. PM stiffens with increasing salt concentration according to two different regimes. At low salt concentration, the membrane Young's normal modulus grows quickly but differentially for the EC and CP leaflets. At higher salt concentration, both leaflets behave similarly and their stiffness converges toward the native environment value. Changes in pH do not affect PM stiffness; however, the crystal assembly is less pronounced at pH > or = 10. Lipid mobility is high in the CP leaflet, especially at low salt concentration, but negligible in the EC leaflet regardless of pH or salt concentration. An independent lipid mobility study by solid-state NMR confirms and quantifies the atomic force microscopy qualitative observations.
Collapse
Affiliation(s)
- Kislon Voïtchovsky
- Interdisciplinary Research Collaboration in Bionanotechnology, Department of Physics, Clarendon Laboratory, University of Oxford, Oxford OX1 3PU, United Kingdom.
| | | | | | | | | |
Collapse
|
11
|
Kim DT, Blanch HW, Radke CJ. Imaging of reconstituted purple membranes by atomic force microscopy. Colloids Surf B Biointerfaces 2005; 41:263-76. [PMID: 15748822 DOI: 10.1016/j.colsurfb.2005.01.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2004] [Revised: 12/30/2004] [Accepted: 01/03/2005] [Indexed: 11/27/2022]
Abstract
The organization of bacteriorhodopsin (bR) within reconstituted purple membranes (RPM) was examined using atomic force microscopy (AFM). Five reconstituted species were examined: RPM 3 (bR/native polar lipids/dimyristoylphosphatidylcholine (DMPC) in a 1:9:14 molar ratio), RPM 4 (bR/native polar lipids in a 1:7 molar ratio), RPM 5 (bR/native polar lipids/1,2-di-O-phytanyl-sn-glycerol in a 1:3.5:6.1 molar ratio), RPM 6 (bR/native polar lipids/1,2-di-O-phytanyl-sn-glycero-3-phosphocholine in a 1:3.5:4.9 molar ratio), and RPM 7 (bR/native polar lipids/1,2-diphytanoyl-sn-glycero-3-[phospho-L-serine] in a 1:3.5:4.6 molar ratio). RPM 3 patches adsorbed onto mica exhibit domains of crystallized bR trimers arranged in a hexagonal packing structure, similar to those found in native purple membrane (NPM). These domains are enclosed by DMPC-rich regions. RPM 4 patches were observed to have larger domains of crystallized bR, with trimer orientation 30 degrees different from that found in NPM. The bR-rich domains are enclosed by a large, protein-free, lipid-rich region. The topography of RPM 5 was difficult to resolve as the surface had no discernable patterns or structure. The topographies of RPM 6 and 7 were similar to that found in RPM 3 in that higher domains were formed within the patch adsorbed onto mica. They may contain protein-rich regions, but clear images of protein arrangement could not be obtained using AFM. This may be a result of imaging limitations or of the lack of organization of bR within these domains.
Collapse
Affiliation(s)
- David T Kim
- Department of Chemical Engineering, University of California, 201 Gilman Hall, Berkeley, CA 94720-1462, USA
| | | | | |
Collapse
|
12
|
Saitô H, Yamamoto K, Tuzi S, Yamaguchi S. Backbone dynamics of membrane proteins in lipid bilayers: the effect of two-dimensional array formation as revealed by site-directed solid-state 13C NMR studies on [3-13C]Ala- and [1-13C]Val-labeled bacteriorhodopsin. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2003; 1616:127-36. [PMID: 14561470 DOI: 10.1016/j.bbamem.2003.08.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have recorded site-directed solid-state 13C NMR spectra of [3-13C]Ala- and [1-13C]Val-labeled bacteriorhodopsin (bR) as a typical membrane protein in lipid bilayers, to examine the effect of formation of two-dimensional (2D) lattice or array of the proteins toward backbone dynamics, to search the optimum condition to be able to record full 13C NMR signals from whole area of proteins. Well-resolved 13C NMR signals were recorded for monomeric [3-13C]Ala-bR in egg phosphatidylcholine (PC) bilayer at ambient temperature, although several 13C NMR signals from the loops and transmembrane alpha-helices were still suppressed. This is because monomeric bR reconstituted into egg PC, dimyristoylphosphatidylcholine (DMPC) or dipalmytoylphosphatidylcholine (DPPC) bilayers undergoes conformational fluctuations with frequency in the order of 10(4)-10(5) Hz at ambient temperature, which is interfered with frequency of magic angle spinning or proton decoupling. It turned out, however, that the 13C NMR signals of purple membrane (PM) were almost fully recovered in gel phase lipids of DMPC or DPPC bilayers at around 0 degrees C. This finding is interpreted in terms of aggregation of bR in DMPC or DPPC bilayers to 2D hexagonal array in the presence of endogenous lipids at low temperature, resulting in favorable backbone dynamics for 13C NMR observation. It is therefore concluded that [3-13C]Ala-bR reconstituted in egg PC, DMPC or DPPC bilayers at ambient temperature, or [3-13C]Ala- and [1-13C]Val-bR at low temperature gave rise to well-resolved 13C NMR signals, although they are not always completely the same as those of 2D hexagonal lattice from PM.
Collapse
Affiliation(s)
- Hazime Saitô
- Department of Life Science, Graduate School of Science, Himeji Institute of Technology, Harima Science Garden City, Kamigori, Hyogo 678-1297, Japan.
| | | | | | | |
Collapse
|
13
|
Abstract
Bacteriorhodopsin (BR) and specific lipid molecules self-assemble into a quasi two-dimensional lattice structure known as the purple membrane (PM). In the PM, BR molecules exist in a trimeric form with lipid molecules present in the space enclosed by each trimeric unit and in the inter-trimer space. These trimeric units, which have a roughly circular cross-section, are arranged in hexagonal patterns with long-ranged crystalline order. In this work, we investigate the self-assembly of BR in the PM via Monte Carlo simulations of a two-dimensional model of the membrane and proteins. The protein molecules are modeled as 120 degrees sectors of a circle and the lipid molecules enter into the model through effective protein-protein interactions. The sectors cannot overlap with each other, and in addition to this excluded volume interaction there are site-site attractive interactions between specific points of the proteins to mimic interactions between helices on the proteins and lipid-induced interactions. At low values of the attractive well depth, the proteins are found in the monomeric form at all concentrations. At moderate and high values of the attractive well depth, trimers are formed as the concentration increases, and with a further increase in concentration the trimers organize into a hexagonal lattice. The interactions between the proteins and those induced by the intra-trimer lipids play an equally important role in the formation of trimers and the lattice. The lipids in the inter-trimer space cause the trimers to orient in a specific direction in the hexagonal crystal lattice.
Collapse
|
14
|
Nollert P, Qiu H, Caffrey M, Rosenbusch JP, Landau EM. Molecular mechanism for the crystallization of bacteriorhodopsin in lipidic cubic phases. FEBS Lett 2001; 504:179-86. [PMID: 11532451 DOI: 10.1016/s0014-5793(01)02747-8] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Crystals of transmembrane proteins may be grown from detergent solutions or in a matrix of membranous lipid bilayers existing in a liquid crystalline state and forming a cubic phase (in cubo). While crystallization in micellar solutions appears analogous to that for soluble proteins, crystallization in lipidic matrices is poorly understood. As this method was shown to be applicable to several membrane proteins, understanding its mechanism will facilitate a rational design of crystallization, minimizing the laborious screening of a large number of parameters. Using polarization microscopy and low-angle X-ray diffraction, experimental evidence is provided to support a mechanistic model for the in cubo crystallization of bacteriorhodopsin in a lipid matrix. Membrane proteins are thought to reside in curved lipid bilayers, to diffuse into patches of lower curvature and to incorporate into lattices which associate to form highly ordered three-dimensional crystals. Critical testing of this model is necessary to generalize it to other membrane proteins.
Collapse
Affiliation(s)
- P Nollert
- Department of Biochemistry and Biophysics, University of California San Francisco, 94134-0448, USA
| | | | | | | | | |
Collapse
|
15
|
Affiliation(s)
- M C Sabra
- Department of Chemistry, Technical University of Denmark, Lyngby, Denmark
| | | |
Collapse
|
16
|
Krebs MP, Isenbarger TA. Structural determinants of purple membrane assembly. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1460:15-26. [PMID: 10984587 DOI: 10.1016/s0005-2728(00)00126-2] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The purple membrane is a two-dimensional crystalline lattice formed by bacteriorhodopsin and lipid molecules in the cytoplasmic membrane of Halobacterium salinarum. High-resolution structural studies, in conjunction with detailed knowledge of the lipid composition, make the purple membrane one of the best models for elucidating the forces that are responsible for the assembly and stability of integral membrane protein complexes. In this review, recent mutational efforts to identify the structural features of bacteriorhodopsin that determine its assembly in the purple membrane are discussed in the context of structural, calorimetric and reconstitution studies. Quantitative evidence is presented that interactions between transmembrane helices of neighboring bacteriorhodopsin molecules contribute to purple membrane assembly. However, other specific interactions, particularly between bacteriorhodopsin and lipid molecules, may provide the major driving force for assembly. Elucidating the molecular basis of protein-protein and protein-lipid interactions in the purple membrane may provide insights into the formation of integral membrane protein complexes in other systems.
Collapse
Affiliation(s)
- M P Krebs
- Department of Biomolecular Chemistry, University of Wisconsin Medical School, 53706-1532, Madison, WI, USA.
| | | |
Collapse
|
17
|
Gil T, Ipsen JH, Mouritsen OG, Sabra MC, Sperotto MM, Zuckermann MJ. Theoretical analysis of protein organization in lipid membranes. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1376:245-66. [PMID: 9804966 DOI: 10.1016/s0304-4157(98)00022-7] [Citation(s) in RCA: 165] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The fundamental physical principles of the lateral organization of trans-membrane proteins and peptides as well as peripheral membrane proteins and enzymes are considered from the point of view of the lipid-bilayer membrane, its structure, dynamics, and cooperative phenomena. Based on a variety of theoretical considerations and model calculations, the nature of lipid-protein interactions is considered both for a single protein and an assembly of proteins that can lead to aggregation and protein crystallization in the plane of the membrane. Phenomena discussed include lipid sorting and selectivity at protein surfaces, protein-lipid phase equilibria, lipid-mediated protein-protein interactions, wetting and capillary condensation as means of protein organization, mechanisms of two-dimensional protein crystallization, as well as non-equilibrium organization of active proteins in membranes. The theoretical findings are compared with a variety of experimental data.
Collapse
Affiliation(s)
- T Gil
- Department of Chemistry, Technical University of Denmark, Building 206, DK-2800 Lyngby, Denmark
| | | | | | | | | | | |
Collapse
|
18
|
Sabra MC, Uitdehaag JC, Watts A. General model for lipid-mediated two-dimensional array formation of membrane proteins: application to bacteriorhodopsin. Biophys J 1998; 75:1180-8. [PMID: 9726920 PMCID: PMC1299793 DOI: 10.1016/s0006-3495(98)74037-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Based on experimental evidence for 2D array formation of bacteriorhodopsin, we propose a general model for lipid-mediated 2D array formation of membrane proteins in lipid bilayers. The model includes two different lipid species, "annular" lipids and "neutral" lipids, and one protein species. The central assumption of the model is that the annular lipids interact more strongly with the protein than with the neutral lipids. Monte Carlo simulations performed on this model show that 2D arrays of proteins only form when there are annular lipids present. In addition, no arrays form if all of the lipids present are annular lipids. The geometry of the observed arrays is for the most part hexagonal. However, for a certain range of low annular lipid/protein ratios, arrays form that have geometries other than hexagonal. Using the assumption that the hydrocarbon chains of the annular lipids are restricted in motion when close to a protein, we expand the model to include a ground state and an excited state of the annular lipids. The main result from the extended model is that within a certain temperature range, increasing the temperature will lead to larger and more regular protein arrays.
Collapse
Affiliation(s)
- M C Sabra
- Department of Biochemistry, University of Oxford, England
| | | | | |
Collapse
|
19
|
Terstegen F, Buβ V. Influence of DFT-calculated electron correlation on energies and geometries of retinals and of retinal derivatives related to the bacteriorhodopsin and rhodopsin chromophores. ACTA ACUST UNITED AC 1998. [DOI: 10.1016/s0166-1280(98)90243-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
20
|
Terstegen F, Buß V. Geometries and interconversion pathways of free and protonated β-ionone Schiff bases. An ab initio study of photoreceptor chromophore model compounds. Chem Phys 1997. [DOI: 10.1016/s0301-0104(97)00194-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
21
|
Krebs MP, Li W, Halambeck TP. Intramembrane substitutions in helix D of bacteriorhodopsin disrupt the purple membrane. J Mol Biol 1997; 267:172-83. [PMID: 9096216 DOI: 10.1006/jmbi.1996.0848] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The Halobacterium salinarium purple membrane is a two-dimensional crystalline lattice containing bacteriorhodopsin (BR) and lipid. To test whether molecular packing within the lipid bilayer influences the structural stability of the lattice, BR mutants substituted on the membrane-embedded surface of the protein were expressed in H. salinarium. Lattice stability was assessed by equilibrium density centrifugation of cell lysates containing similar amounts of BR. BR was distributed in low (1.12 to 1.15 g/ml) and high density (1.18 g/ml) membrane fractions. The high density fraction comprised 89% of the total BR in wild-type, but only 19% (G113L), 29% (I117A), 52% (G116L) and 79% (I117F) in the mutants. In each case, this fraction contained BR in a lattice form: its absorption maximum was blue-shifted by < or = 4 nm relative to the wild-type lattice, its light-dark difference spectrum was normal, and its circular dichroism spectrum retained a bilobed feature characteristic of the lattice. Thus, the substitutions do not significantly alter the tertiary structure of the protein. In the low density fraction, the absorption maximum of BR was blue-shifted by 2 to 4 nm relative to the corresponding high density fraction, and the bilobed circular dichroism feature was attenuated (I117F and G116L) or absent (G113L and I117A). This suggests that the substitutions disrupt lattice stability, causing an accumulation of BR monomers or small aggregates. These results support a model in which the BR lattice is stabilized by hydrophobic packing at specific protein-protein and protein-lipid interfaces within the membrane bilayer.
Collapse
Affiliation(s)
- M P Krebs
- Department of Biomolecular Chemistry, University of Wisconsin Medical School, Madison 53706-1532, USA
| | | | | |
Collapse
|
22
|
All-trans- and 11-cis-retinal, their N-methyl Schiff base and N-methyl protonated Schiff base derivatives: a comparative ab initio study. ACTA ACUST UNITED AC 1996. [DOI: 10.1016/s0166-1280(96)04559-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
23
|
|
24
|
Watts A, Sternberg B, Ulrich AS, Whiteway CA, Seifert G, Sami M, Fisher P, Heyn MP, Wallat I. Bacteriorhodopsin: the effect of bilayer thickness on 2D-array formation, and the structural re-alignment of retinal through the photocycle. Biophys Chem 1995; 56:41-6. [PMID: 17023316 DOI: 10.1016/0301-4622(95)00013-n] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
From our earlier extensive protein-lipid reconstitution studies, the conditions under which bacteriorhodopsin forms organised 2D arrays in large unilamellar vesicles have been established using freeze-fracture electron microscopy. In a background bilayer matrix of phosphatidylcholine (diC(14:0)), the protein can form arrays only when the anionic purple membrane lipid, phosphatidylglycerol phosphate (or the sulphate derivative) is present. Here we have now extended this work to investigate the effect of bilayer thickness on array formation. Phosphatidylcholines with various chain lengths (diC(12:0), diC(14:0) and diC(16:0)) and which form bilayers of well defined bilayer thickness, have been used as the matrix into which bacteriorhodopsin, together with minimal levels (c. 4-10 lipids per bacteriorhodopsin) of diphytanyl phosphatidyl-glycerol phosphate, has been reconstituted. Arrays are formed in all complexes and bhickness appears only to alter the type of array formed, either as an orthogonal or as an hexagonal array. Secondly, we have previously deduced the entire conformation of retinal within the bacteriorhodopsin binding pocket in oriented purple membrane fragments. Using solid state deuterium NMR of the specifically deutero-methylated retinal labelled at each of the methyl positions in the molecule, the C-CD(3) bond vectors of the chromophore have been resolved to +/- 2 degrees . The ring conformation is 6-S-trans, but the polyene chain is slightly curved when in the protein binding site. Here, we describe studies on the protein in both the ground state and the trapped M(412)-state of the photocycle, to show that the orientation of the central methyl group (C(19)) on the polyene chain, which is at 40 degrees +/- 1 degrees with respect to the membrane normal, only changes its orientation by approximately 4 degrees upon 13-cis-isomerization. Thus, it is the Schiff base end of the chromophore which moves upon light incidence acting as a local switch on the protein in the photocycle, whilst the ring end of the chromophore moves rather less.
Collapse
Affiliation(s)
- A Watts
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | | | | | | | | | | | | | | | | |
Collapse
|