1
|
Rao BD, Shrivastava S, Pal S, Chattopadhyay A. Effect of Local Anesthetics on the Organization and Dynamics of Hippocampal Membranes: A Fluorescence Approach. J Phys Chem B 2018; 123:639-647. [DOI: 10.1021/acs.jpcb.8b10232] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Bhagyashree D. Rao
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
- CSIR-Indian Institute of Chemical Technology, Uppal Road, Hyderabad 500 007, India
- Academy of Scientific and Innovative Research, Ghaziabad 201 002, India
| | - Sandeep Shrivastava
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
| | - Sreetama Pal
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
- CSIR-Indian Institute of Chemical Technology, Uppal Road, Hyderabad 500 007, India
- Academy of Scientific and Innovative Research, Ghaziabad 201 002, India
| | - Amitabha Chattopadhyay
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
- Academy of Scientific and Innovative Research, Ghaziabad 201 002, India
| |
Collapse
|
2
|
Pallavi P, Sk B, Ahir P, Patra A. Tuning the Förster Resonance Energy Transfer through a Self-Assembly Approach for Efficient White-Light Emission in an Aqueous Medium. Chemistry 2017; 24:1151-1158. [DOI: 10.1002/chem.201704437] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Indexed: 12/21/2022]
Affiliation(s)
- Pragyan Pallavi
- Department of Chemistry; Indian Institute of Science Education and Research; Bhopal India
| | - Bahadur Sk
- Department of Chemistry; Indian Institute of Science Education and Research; Bhopal India
| | - Palak Ahir
- Department of Chemistry; Indian Institute of Science Education and Research; Bhopal India
| | - Abhijit Patra
- Department of Chemistry; Indian Institute of Science Education and Research; Bhopal India
| |
Collapse
|
3
|
Effect of Self-Assemblies on the Dynamics of the Briggs–Rauscher Reaction. J SURFACTANTS DETERG 2017. [DOI: 10.1007/s11743-017-1956-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
4
|
Gull U, Peerzada GM, Ganaie NB, Rashid S. Effect of self-assemblies on the dynamics of phloroglucinol-based Belousov-Zhabotinsky reaction: analytical approach. Colloid Polym Sci 2016. [DOI: 10.1007/s00396-015-3800-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
5
|
Mitra M, Chaudhuri A, Patra M, Mukhopadhyay C, Chakrabarti A, Chattopadhyay A. Organization and Dynamics of Tryptophan Residues in Brain Spectrin: Novel Insight into Conformational Flexibility. J Fluoresc 2015; 25:707-17. [DOI: 10.1007/s10895-015-1556-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 03/05/2015] [Indexed: 10/23/2022]
|
6
|
Gao L, Xia H, Wang X, Li L, Chen H. Dansyl-labeled anionic amphiphile with a hexadecanoic carbon chain: synthesis and detection for shape transitions in organized molecular assemblies. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2015; 139:222-228. [PMID: 25561301 DOI: 10.1016/j.saa.2014.11.113] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Revised: 11/22/2014] [Accepted: 11/25/2014] [Indexed: 06/04/2023]
Abstract
The probing properties of a new fluorophore-labeled anionic surfactant, sodium 16-(N-dansyl)aminocetylate (16-DAN-ACA) were investigated systematically in molecular assemblies, especially in the transitions between micelles and vesicles. 16-DAN-ACA can efficiently differentiate the two different aggregate types in mixed cationic and anionic surfactant systems. The fluorescence anisotropy of 16-DAN-ACA was found to be sensitive for directly detecting the micellar growth in micelles containing oppositely charged surfactants; both cationic cetyltrimethylammonium bromide (CTAB) systems and anionic sodium dodecyl sulfate (SDS) systems were studied. The results indicated that the 16-DAN-ACA is a good fluorescent probe for differentiating the different aggregates, and even more can be used to detect the micellar growth.
Collapse
Affiliation(s)
- Lining Gao
- Engineering Research Center of Transportation Materials (Ministry of Education), School of Materials Science and Engineering, Chang'an University, Xi'an 710064, PR China.
| | - Huiyun Xia
- Engineering Research Center of Transportation Materials (Ministry of Education), School of Materials Science and Engineering, Chang'an University, Xi'an 710064, PR China
| | - Xiaoman Wang
- Engineering Research Center of Transportation Materials (Ministry of Education), School of Materials Science and Engineering, Chang'an University, Xi'an 710064, PR China
| | - Li Li
- Engineering Research Center of Transportation Materials (Ministry of Education), School of Materials Science and Engineering, Chang'an University, Xi'an 710064, PR China
| | - Huaxin Chen
- Engineering Research Center of Transportation Materials (Ministry of Education), School of Materials Science and Engineering, Chang'an University, Xi'an 710064, PR China
| |
Collapse
|
7
|
Chaudhuri A, Chattopadhyay A. Lipid binding specificity of bovine α-lactalbumin: A multidimensional approach. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:2078-86. [DOI: 10.1016/j.bbamem.2014.04.027] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2014] [Revised: 04/27/2014] [Accepted: 04/28/2014] [Indexed: 10/25/2022]
|
8
|
Influence of Micellar Propinquity on Dynamics of Ce(IV)-Catalyzed BZ Oscillatory Reaction under Stirred Conditions. INT J CHEM KINET 2014. [DOI: 10.1002/kin.20851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
9
|
Anand U, Mukherjee S. Microheterogeneity and microviscosity of F127 micelle: the counter effects of urea and temperature. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:1012-1021. [PMID: 24410288 DOI: 10.1021/la4049192] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
F127 is the most widely studied triblock copolymer and due to the presence of very long polypropylene oxide (PPO) and polyethylene oxide (PEO) groups, F127 micelle has different microenvironments clearly separated into core, corona, and peripheral regions. Urea has been known to have adverse effects on the micellar properties and causes demicellization and solvation; on the other hand, rise in temperature causes micellization and solvent evacuation from the core and corona regions. In the present study, we have investigated the microheterogeneity of the core, corona, and peripheral regions of the F127 micelle using red edge excitation shift (REES) at different temperatures and urea concentrations and correlated the effect of both on the micellar system. It was found that the temperature counteracts the effect of urea and also that the counteraction is more prominent in the core region with respect to corona, and the peripheral region is least affected. Also, the core and corona regions are very much heterogeneous, while the peripheral region is more of a homogeneous nature. Using time-resolved fluorescence anisotropy, we found that the microviscosity within the micelles vary in the order of core > corona > peripheral region, and urea has a general tendency to reduce the microviscosity, especially for core and corona regions. On the other hand, rise in temperature initially increases and then decreases the microviscosity throughout, and at elevated temperatures the effect of urea is being dominated by the effect of temperature, thereby establishing the counter effects of temperature and urea on the F127 micellar system.
Collapse
Affiliation(s)
- Uttam Anand
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal , Indore By-Pass Road, Bhauri, Bhopal 462 066, Madhya Pradesh, India
| | | |
Collapse
|
10
|
Photophysical properties of 4,4-diaminodiphenyl sulfone in micelles and the role of BF-anion on micellar aggregation. J Photochem Photobiol A Chem 2012. [DOI: 10.1016/j.jphotochem.2012.09.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
11
|
Chaudhuri A, Haldar S, Chattopadhyay A. Structural transition in micelles: novel insight into microenvironmental changes in polarity and dynamics. Chem Phys Lipids 2012; 165:497-504. [DOI: 10.1016/j.chemphyslip.2011.09.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Revised: 09/15/2011] [Accepted: 09/16/2011] [Indexed: 01/23/2023]
|
12
|
Application of NBD-Labeled Lipids in Membrane and Cell Biology. SPRINGER SERIES ON FLUORESCENCE 2012. [DOI: 10.1007/4243_2012_43] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
|
13
|
Haldar S, Chaudhuri A, Chattopadhyay A. Organization and dynamics of membrane probes and proteins utilizing the red edge excitation shift. J Phys Chem B 2011; 115:5693-706. [PMID: 21428321 DOI: 10.1021/jp200255e] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Dynamics of confined water has interesting implications in the organization and function of molecular assemblies such as membranes. A direct consequence of this type of organization is the restriction imposed on the mobility of the constituent structural units. Interestingly, this restriction (confinement) of mobility couples the motion of solvent (water) molecules with the slow moving molecules in the assembly. It is in this context that the red edge excitation shift (REES) represents a sensitive approach to monitor the environment and dynamics around a fluorophore in such organized assemblies. A shift in the wavelength of maximum fluorescence emission toward higher wavelengths, caused by a shift in the excitation wavelength toward the red edge of the absorption band, is termed REES. REES relies on slow solvent reorientation in the excited state of a fluorophore that can be used to monitor the environment and dynamics around a fluorophore in a host assembly. In this article, we focus on the application of REES to monitor organization and dynamics of membrane probes and proteins.
Collapse
Affiliation(s)
- Sourav Haldar
- Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Uppal Road, Hyderabad 500 007 India
| | | | | |
Collapse
|
14
|
Gao L, Zhao L, Huang X, Xu B, Yan Y, Huang J. A surfactant type fluorescence probe for detecting micellar growth. J Colloid Interface Sci 2011; 354:256-60. [DOI: 10.1016/j.jcis.2010.10.037] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Revised: 10/13/2010] [Accepted: 10/14/2010] [Indexed: 11/25/2022]
|
15
|
Transbilayer organization of membrane cholesterol at low concentrations: Implications in health and disease. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1808:19-25. [PMID: 21035427 DOI: 10.1016/j.bbamem.2010.10.013] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2010] [Revised: 10/20/2010] [Accepted: 10/22/2010] [Indexed: 02/06/2023]
Abstract
Cholesterol is an essential and representative lipid in higher eukaryotic cellular membranes and is often found distributed nonrandomly in domains in biological membranes. A large body of literature exists on the organization of cholesterol in plasma membranes or membranes with high cholesterol content. However, very little is known about organization of cholesterol in membranes containing low amounts of cholesterol such as the endoplasmic reticulum or inner mitochondrial membranes. In this review, we have traced the discovery and subsequent development of the concept of transbilayer cholesterol dimers (domains) in membranes at low concentrations. We have further discussed the role of membrane curvature and thickness on the transbilayer organization of cholesterol. Interestingly, this type of cholesterol organization could be relevant in cellular sorting and trafficking, and in pathological conditions.
Collapse
|
16
|
Perturbation mechanism and phase transition of AOT aggregates in the Fe(II)[batho(SO3)2]3 – catalyzed aqueous Belousov–Zhabotinsky reaction. Chem Phys Lett 2010. [DOI: 10.1016/j.cplett.2009.12.050] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
17
|
Gao L, Song Q, Huang X, Huang J. A new surfactant-fluorescence probe for detecting shape transitions in self-assembled systems. J Colloid Interface Sci 2008; 323:420-5. [DOI: 10.1016/j.jcis.2008.04.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2008] [Revised: 04/02/2008] [Accepted: 04/05/2008] [Indexed: 10/22/2022]
|
18
|
Nguyen TQ, Martel R, Bushey M, Avouris P, Carlsen A, Nuckolls C, Brus L. Self-assembly of 1-D organic semiconductor nanostructures. Phys Chem Chem Phys 2007; 9:1515-32. [PMID: 17429546 DOI: 10.1039/b609956d] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This review focuses on the molecular design and self-assembly of a new class of crowded aromatics that form 1-D nanostructures via hydrogen bonding and pi-pi interactions. These molecules have a permanent dipole moment that sums as the subunits self assemble into molecular stacks. The assembly of these molecular stacks can be directed with electric fields. Depending on the nature of the side-chains, molecules can obtain the face-on or edge-on orientation upon the deposition onto a surface via spin cast technique. Site-selective steady state fluorescence, time-resolved fluorescence, and various types of scanning probe microscopy measurements detail the intermolecular interactions that drive the aromatic molecules to self-assemble in solution to form well-ordered columnar stacks. These nanostructures, formed in solution, vary in their number, size, and structure depending on the functional groups, solvent, and concentration used. Thus, the substituents/side-groups and the proper choice of the solvent can be used to tune the intermolecular interactions. The 1-D stacks and their aggregates can be easily transferred by solution casting, thus allowing a simple preparation of molecular nanostructures on different surfaces.
Collapse
Affiliation(s)
- Thuc-Quyen Nguyen
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106, USA.
| | | | | | | | | | | | | |
Collapse
|
19
|
Excitation wavelength dependent fluorescence behavior of the room temperature ionic liquids and dissolved dipolar solutes. J Photochem Photobiol A Chem 2006. [DOI: 10.1016/j.jphotochem.2006.01.003] [Citation(s) in RCA: 112] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
20
|
Chen J, Zhang J, Wu Y, Han B, Liu D, Li Z, Li J, Ai X. Fluorescence studies on the microenvironments of proteins in CO2-expanded reverse micellar solutions. J Supercrit Fluids 2006. [DOI: 10.1016/j.supflu.2005.11.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
21
|
Paul A. Observations of the Effect of Anionic, Cationic, Neutral, and Zwitterionic Surfactants on the Belousov−Zhabotinsky Reaction. J Phys Chem B 2005; 109:9639-44. [PMID: 16852160 DOI: 10.1021/jp044519j] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In this paper we report the experimental observations of the effects of various surfactants on the oscillations of the ferroin-catalyzed Belousov-Zhabotinsky (BZ) reaction. The oscillations are followed by observing the change in absorbance at 510 nm due to ferroin in a well-stirred closed BZ reacting system. We have used sodium dodecyl sulfate (SDS) as the anionic surfactant, cetyl trimethylammonium bromide (CTAB) as the cationic surfactant, Triton X-100 as the neutral surfactant, and 3-[(3-cholamidopropyl)dimethylammonio)]-1-propanesulfonate (CHAPS) as the zwitterionic surfactant. In general, we observed that there is a change in the oscillation behavior in the presence of each of these surfactants above their critical micellar concentrations. For different surfactants, the time-dependent evolution of the oscillations is found to be characteristic of the surfactant. The results of our study suggest that the evolution of oscillations is most regular in the presence of micelles of SDS.
Collapse
Affiliation(s)
- Anumita Paul
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati 781 039 India.
| |
Collapse
|
22
|
Mukherjee S, Chattopadhyay A. Influence of ester and ether linkage in phospholipids on the environment and dynamics of the membrane interface: a wavelength-selective fluorescence approach. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:287-293. [PMID: 15620316 DOI: 10.1021/la048027+] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We have monitored the environment and dynamics of the membrane interface formed by the ester-linked phospholipid 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and the ether-linked phospholipid 1,2-dihexadecyl-sn-glycero-3-phosphocholine (DHPC) utilizing the wavelength-selective fluorescence approach and using the fluorescent membrane probe 2-(9-anthroyloxy)stearic acid (2-AS). This interfacially localized probe offers a number of advantages over those which lack a fixed location in the membrane. When incorporated in membranes formed by DPPC and DHPC, 2-AS exhibits red edge excitation shift (REES) of 14 and 8 nm, respectively. This implies that the rate of solvent reorientation, as sensed by the interfacial anthroyloxy probe, in ester-linked DPPC membranes is slow compared to the rate of solvent reorientation in ether-linked DHPC membranes. In addition, the fluorescence polarization values of 2-AS are found to be higher in DHPC membranes than in DPPC membranes. This is further supported by wavelength-dependent changes in fluorescence polarization and lifetime. Taken together, these results are useful in understanding the role of interfacial chemistry on membrane physical properties.
Collapse
Affiliation(s)
- Soumi Mukherjee
- Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, India
| | | |
Collapse
|
23
|
Mukherjee S, Raghuraman H, Dasgupta S, Chattopadhyay A. Organization and dynamics of N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)-labeled lipids: a fluorescence approach. Chem Phys Lipids 2004; 127:91-101. [PMID: 14706743 DOI: 10.1016/j.chemphyslip.2003.09.004] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Lipids that are labeled with the NBD (7-nitrobenz-2-oxa-1,3-diazol-4-yl) group are widely used as fluorescent analogues of native lipids in biological and model membranes to monitor a variety of processes. NBD-labeled lipids have previously been used to monitor the organization and dynamics of molecular assemblies such as membranes, micelles and reverse micelles utilizing the wavelength-selective fluorescence approach. In this paper, we have characterized the organization and dynamics of various NBD-labeled lipids using red edge excitation shift (REES) and other fluorescence approaches which include analysis of membrane penetration depths of the NBD group using the parallax method. We show here that the environment and location experienced by the NBD group of the NBD-labeled lipids could depend on the ionization state of the lipid. This could have potentially important implications in future studies involving NBD-labeled lipids as tracers in a cellular context.
Collapse
Affiliation(s)
- Soumi Mukherjee
- Centre for Cellular and Molecular Biology, Hyderabad 500 007, India
| | | | | | | |
Collapse
|
24
|
Chattopadhyay A, Rawat SS, Kelkar DA, Ray S, Chakrabarti A. Organization and dynamics of tryptophan residues in erythroid spectrin: novel structural features of denatured spectrin revealed by the wavelength-selective fluorescence approach. Protein Sci 2004; 12:2389-403. [PMID: 14573853 PMCID: PMC2366958 DOI: 10.1110/ps.03302003] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
We have investigated the organization and dynamics of the functionally important tryptophan residues of erythroid spectrin in native and denatured conditions utilizing the wavelength-selective fluorescence approach. We observed a red edge excitation shift (REES) of 4 nm for the tryptophans in the case of spectrin in its native state. This indicates that tryptophans in spectrin are localized in a microenvironment of restricted mobility, and that the regions surrounding the spectrin tryptophans offer considerable restriction to the reorientational motion of the water dipoles around the excited state tryptophans. Interestingly, spectrin exhibits a REES of 3 nm even when denatured in 8 M urea. This represents the first report of a denatured protein displaying REES. Observation of REES in the denatured state implies that some of the structural and dynamic features of this microenvironment around the spectrin tryptophans are retained even when the protein is denatured. Fluorescence quenching data of denatured spectrin support this conclusion. In addition, we have deduced the organization and dynamics of the hydrophobic binding site of the polarity-sensitive fluorescent probe PRODAN that binds erythroid spectrin with high affinity. When bound to spectrin, PRODAN exhibits a REES of 9 nm. Because PRODAN binds to a hydrophobic site in spectrin, such a result would directly imply that this region of spectrin offers considerable restriction to the reorientational motion of the solvent dipoles around the excited state fluorophore. The results of our study could provide vital insight into the role of tryptophans in the stability and folding of spectrin.
Collapse
|
25
|
Rawat SS, Kelkar DA, Chattopadhyay A. Monitoring gramicidin conformations in membranes: a fluorescence approach. Biophys J 2004; 87:831-43. [PMID: 15298892 PMCID: PMC1304493 DOI: 10.1529/biophysj.104.041715] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2004] [Accepted: 04/12/2004] [Indexed: 12/16/2022] Open
Abstract
We have monitored the membrane-bound channel and nonchannel conformations of gramicidin utilizing red-edge excitation shift (REES), and related fluorescence parameters. In particular, we have used fluorescence lifetime, polarization, quenching, chemical modification, and membrane penetration depth analysis in addition to REES measurements to distinguish these two conformations. Our results show that REES of gramicidin tryptophans can be effectively used to distinguish conformations of membrane-bound gramicidin. The interfacially localized tryptophans in the channel conformation display REES of 7 nm whereas the tryptophans in the nonchannel conformation exhibit REES of 2 nm which highlights the difference in their average environments in terms of localization in the membrane. This is supported by tryptophan penetration depth measurements using the parallax method and fluorescence lifetime and polarization measurements. Further differences in the average tryptophan microenvironments in the two conformations are brought out by fluorescence quenching experiments using acrylamide and chemical modification of the tryptophans by N-bromosuccinimide. In summary, we report novel fluorescence-based approaches to monitor conformations of this important ion channel peptide. Our results offer vital information on the organization and dynamics of the functionally important tryptophan residues in gramicidin.
Collapse
|
26
|
Kelkar DA, Chattopadhyay A. Depth-Dependent Solvent Relaxation in Reverse Micelles: A Fluorescence Approach. J Phys Chem B 2004. [DOI: 10.1021/jp048645z] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Devaki A. Kelkar
- Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
| | | |
Collapse
|
27
|
Raghuraman H, Chattopadhyay A. Effect of micellar charge on the conformation and dynamics of melittin. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2004; 33:611-22. [PMID: 15071759 DOI: 10.1007/s00249-004-0402-7] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2003] [Revised: 02/12/2004] [Accepted: 03/08/2004] [Indexed: 10/26/2022]
Abstract
Electrostatic interactions play a crucial role in modulating and stabilizing molecular interactions in membranes and membrane-mimetic systems such as micelles. We have monitored the change in the conformation and dynamics of the cationic hemolytic peptide melittin bound to micelles of various charge types, utilizing fluorescence and circular dichroism (CD) spectroscopy. The sole tryptophan of melittin displays a red-edge excitation shift (REES) of 3-6 nm when bound to anionic, nonionic, and zwitterionic micelles. This suggests that melittin is localized in a restricted environment, probably in the interfacial region of the micelles, and this region offers considerable restriction to the reorientational motion of the solvent dipoles around the excited state tryptophan in melittin. Further, the rotational mobility of melittin is considerably reduced in these micelles and is found to be dependent on the surface charge of micelles. Interestingly, our results show that melittin does not partition into cetyltrimethylammonium bromide (CTAB) micelles owing to electrostatic repulsion between melittin and CTAB micelles, both of which carry a positive charge. In addition, the fluorescence lifetime of melittin is modulated in micelles of different charge types. The lowest mean fluorescence lifetime is observed in the case of melittin bound to anionic sodium dodecyl sulfate (SDS) micelles. CD spectroscopy shows that micelles induce significant helicity to melittin, with maximum helicity being induced in the case of melittin bound to SDS micelles. Fluorescence quenching measurements using the neutral aqueous quencher acrylamide show differential accessibility of melittin in various types of micelles. Taken together, our results show that micellar surface charge can modulate the conformation and dynamics of melittin. These results could be relevant to understanding the role of the surface charge of membranes in the interaction of membrane-active, amphiphilic peptides with membranes.
Collapse
Affiliation(s)
- H Raghuraman
- Centre for Cellular and Molecular Biology, Uppal Road, 500 007 Hyderabad, India
| | | |
Collapse
|
28
|
Nguyen TQ, Martel R, Avouris P, Bushey ML, Brus L, Nuckolls C. Molecular Interactions in One-Dimensional Organic Nanostructures. J Am Chem Soc 2004; 126:5234-42. [PMID: 15099108 DOI: 10.1021/ja031600b] [Citation(s) in RCA: 134] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Intermolecular interactions involving pi-pi interaction and hydrogen bonding are used to create one-dimensional molecular nanostructures of hexasubstituted aromatics. Site-selective steady state fluorescence, time-resolved fluorescence, scanning electron microscopy, and atomic force microscopy measurements detail the intermolecular interactions that drive the aromatic molecules to self-assemble in solution to form well-ordered columnar stacks. These nanostructures, formed in solution, vary in their number, size, and structure depending on the solvent used. In addition, our results indicate that the substituents/ side groups and the proper choice of the solvent can be used to tune the intermolecular interactions. The 1D stacks and their aggregates can be easily transferred by solution casting, thus allowing a simple preparation of molecular nanostructures on different surfaces.
Collapse
Affiliation(s)
- Thuc-Quyen Nguyen
- Department of Chemistry, Columbia University, New York, New York 10027 USA.
| | | | | | | | | | | |
Collapse
|
29
|
Raghuraman H, Pradhan SK, Chattopadhyay A. Effect of Urea on the Organization and Dynamics of Triton X-100 Micelles: A Fluorescence Approach. J Phys Chem B 2004. [DOI: 10.1021/jp0365007] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- H. Raghuraman
- Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
| | - Suman K. Pradhan
- Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
| | | |
Collapse
|
30
|
Chattopadhyay A. Exploring membrane organization and dynamics by the wavelength-selective fluorescence approach. Chem Phys Lipids 2003; 122:3-17. [PMID: 12598034 DOI: 10.1016/s0009-3084(02)00174-3] [Citation(s) in RCA: 128] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Wavelength-selective fluorescence comprises a set of approaches based on the red edge effect in fluorescence spectroscopy which can be used to directly monitor the environment and dynamics around a fluorophore in a complex biological system. A shift in the wavelength of maximum fluorescence emission toward higher wavelengths, caused by a shift in the excitation wavelength toward the red edge of absorption band, is termed red edge excitation shift (REES). This effect is mostly observed with polar fluorophores in motionally restricted media such as very viscous solutions or condensed phases where the dipolar relaxation time for the solvent shell around a fluorophore is comparable to or longer than its fluorescence lifetime. REES arises from slow rates of solvent relaxation (reorientation) around an excited state fluorophore which is a function of the motional restriction imposed on the solvent molecules in the immediate vicinity of the fluorophore. Utilizing this approach, it becomes possible to probe the mobility parameters of the environment itself (which is represented by the relaxing solvent molecules) using the fluorophore merely as a reporter group. Further, since the ubiquitous solvent for biological systems is water, the information obtained in such cases will come from the otherwise 'optically silent' water molecules. This makes REES and related techniques extremely useful since hydration plays a crucial modulatory role in a large number of important cellular events, including lipid-protein interactions and ion transport. The interfacial region in membranes, characterized by unique motional and dielectric characteristics, represents an appropriate environment for displaying wavelength-selective fluorescence effects. The application of REES and related techniques (wavelength-selective fluorescence approach) as a powerful tool to monitor the organization and dynamics of probes and peptides bound to membranes, micelles, and reverse micelles is discussed.
Collapse
|
31
|
Chattopadhyay A, Mukherjee S, Raghuraman H. Reverse Micellar Organization and Dynamics: A Wavelength-Selective Fluorescence Approach. J Phys Chem B 2002. [DOI: 10.1021/jp021801m] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - Soumi Mukherjee
- Centre for Cellular & Molecular Biology, Uppal Road, Hyderabad 500 007, India
| | - H. Raghuraman
- Centre for Cellular & Molecular Biology, Uppal Road, Hyderabad 500 007, India
| |
Collapse
|
32
|
Application of the Wavelength-selective Fluorescence Approach to Monitor Membrane Organization and Dynamics. ACTA ACUST UNITED AC 2002. [DOI: 10.1007/978-3-642-56067-5_12] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
|
33
|
Abstract
In 1970, three laboratories independently made a discovery that, for aromatic fluorophores embedded into different rigid and highly viscous media, the spectroscopic properties do not conform to classical rules. The fluorescence spectra can depend on excitation wavelength, and the excited-state energy transfer, if present, fails at the "red" excitation edge. These red-edge effects were related to the existence of excited-state distribution of fluorophores on their interaction energy with the environment and the slow rate of dielectric relaxation of this environment. In these conditions the site-selection can be provided by variation of the energy of illuminating light quanta, and the behaviour of selected species can be followed as a function of time and other variables. These observations found extensive application in different areas of research: colloid and polymer science, molecular biophysics, photochemistry and photobiology. In particular, they led to the development of very productive methods of studying the dynamics of dielectric relaxations in protein and membranes, using the tryptophan emission and the emission of a variety of probes. These studies were extended to the time domain with the observation of new site-selective effects in emission intensity and anisotropy decays. They stimulated the emergence and development of cryogenic energy-selective and single-molecular techniques that became valuable tools in their own right in chemistry and biophysics research. Site-selection effects were discovered for electron-transfer and proton-transfer reactions if they depended on the dynamics of the environment. This review is focused on the progress in the field of red-edge effects, their applications and prospects.
Collapse
Affiliation(s)
- Alexander P Demchenko
- The Palladin Institute of Biochemistry, Academy of Sciences of Ukraine, Kiev 252030, Ukraine.
| |
Collapse
|
34
|
Granjon T, Vacheron MJ, Vial C, Buchet R. Mitochondrial Creatine Kinase Binding to Phospholipids Decreases Fluidity of Membranes and Promotes New Lipid-Induced β Structures As Monitored by Red Edge Excitation Shift, Laurdan Fluorescence, and FTIR. Biochemistry 2001; 40:6016-26. [PMID: 11352737 DOI: 10.1021/bi002293e] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Structural modifications induced by the binding of mitochondrial creatine kinase (mtCK) to saturated and unsaturated phospholipids were monitored by using Laurdan, a membrane probe sensitive to the polarity of the environment. The abrupt change characteristic of a phase transition of lipids alone was attenuated by addition of mtCK. Generalized polarization spectra indicated that mtCK surface binding changed the phospholipid liquid-crystalline state to a more rigid state. Infrared spectra of lipids further strengthened these results: upon mtCK binding, the phospholipid methylene chains had a more rigid conformation than that observed without mtCK at the same temperature. After mtCK binding to vesicles of perdeuterated dimyristoylphosphatidylcholine and nondeuterated dimyristoylphosphatidylglycerol, no lateral phase separation was observed, suggesting that both lipids were rigidified. Moreover, mtCK bound to liposomes exhibited an uncommon red edge excitation shift of 19 nm, while that of the soluble enzyme was only 6 nm. These results indicated that the environment of some mtCK tryptophan residues was motionally restricted. Strong stabilization of the enzyme structure against heat denaturation was observed upon lipid binding. In addition, lipids promoted a new reversible protein-protein or protein-lipid interaction, as evidenced by infrared data showing a slight modification of the beta sheet over alpha helix ratio with formation of a new 1632-cm(-)(1) beta sheet instead of the soluble protein 1636-cm(-)(1) one. Such modifications, inducing a decrease in the fluidity of the mitochondrial membranes, may play a role in vesicle aggregation; they could be implicated in the appearance of contact sites between internal and external mitochondrial membranes.
Collapse
Affiliation(s)
- T Granjon
- Laboratoire de Biomembranes et Enzymes Associés and Laboratoire de Physico-Chimie Biologique, UMR 5013 "Reconnaissance et Transduction Moléculaires", Université Claude Bernard Lyon 1, 69622 Villeurbanne Cedex, France
| | | | | | | |
Collapse
|
35
|
de Foresta B, Gallay J, Sopkova J, Champeil P, Vincent M. Tryptophan octyl ester in detergent micelles of dodecylmaltoside: fluorescence properties and quenching by brominated detergent analogs. Biophys J 1999; 77:3071-84. [PMID: 10585929 PMCID: PMC1300578 DOI: 10.1016/s0006-3495(99)77138-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
The fluorescence properties of tryptophan octyl ester (TOE), a hydrophobic model of Trp in proteins, were investigated in various mixed micelles of dodecylmaltoside (DM) and 7,8-dibromododecyl beta-maltoside (BrDM) or 10,11-dibromoundecanoyl beta-maltoside (BrUM). This study focuses on the mechanism via which these brominated detergents quench the fluorescence of TOE in a micellar system. The experiments were performed at a pH at which TOE is uncharged and almost completely bound to detergent micelles. TOE binding was monitored by its enhanced fluorescence in pure DM micelles or its quenched fluorescence in pure BrUM or BrDM micelles. In DM/BrUM and DM/BrDM mixed micelles, the fluorescence intensity of TOE decreased, as a nonlinear function of the molar fraction of brominated detergent, to almost zero in pure brominated detergent. The indole moiety of TOE is therefore highly accessible to the bromine atoms located on the detergent alkyl chain because quenching by bromines occurs by direct contact with the fluorophore. TOE is simultaneously poorly accessible to iodide (I(-)), a water-soluble collisional quencher. TOE time-resolved fluorescence intensity decay is heterogeneous in pure DM micelles, with four lifetimes (from 0.2 to 4.4 ns) at the maximum emission wavelength. Such heterogeneity may arise from dipolar relaxation processes in a motionally restricted medium, as suggested by the time-dependent (nanoseconds) red shift (11 nm) of the TOE emission spectrum, and from the existence of various TOE conformations. Time-resolved quenching experiments for TOE in mixed micelles showed that the excited-state lifetime values decreased only slightly with increases in the proportion of BrDM or BrUM. In contrast, the relative amplitude of the component with the longest lifetime decreased significantly relative to that of the short-lived species. This is consistent with a mainly static mechanism for the quenching of TOE by brominated detergents. Molecular modeling of TOE (in vacuum and in water) suggested that the indole ring was stabilized by folding back upon the octyl chain, forming a hairpin conformation. Within micelles, the presence of such folded conformations, making it possible for the entire molecule to be located in the hydrophobic part of the micelle, is consistent with the results of fluorescence quenching experiments. TOE rotational correlation time values, in the nanosecond range, were consistent with a hindered rotation of the indole moiety and a rotation of the complete TOE molecule in the pure DM or mixed detergent micelles. These results, obtained with a simple micellar model system, provide a basis for the interpretation of fluorescence quenching by brominated detergents in more complex systems such as protein- or peptide-detergent complexes.
Collapse
Affiliation(s)
- B de Foresta
- Section de Biophysique des Protéines et des Membranes, Département de Biologie Cellulaire et Moléculaire et URA 2096 (CNRS), CEA Saclay, 91191 Gif-sur-Yvette, France.
| | | | | | | | | |
Collapse
|
36
|
Chattopadhyay A, Mukherjee S. Red Edge Excitation Shift of a Deeply Embedded Membrane Probe: Implications in Water Penetration in the Bilayer. J Phys Chem B 1999. [DOI: 10.1021/jp991303m] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Sushmita Mukherjee
- Centre for Cellular & Molecular Biology, Uppal Road, Hyderabad 500 007, India
| |
Collapse
|
37
|
Ghosh AK, Rukmini R, Chattopadhyay A. Modulation of tryptophan environment in membrane-bound melittin by negatively charged phospholipids: implications in membrane organization and function. Biochemistry 1997; 36:14291-305. [PMID: 9398147 DOI: 10.1021/bi971933j] [Citation(s) in RCA: 124] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Melittin is a cationic hemolytic peptide isolated from the European honey bee, Apis mellifera. Since the association of the peptide in the membrane is linked with its physiological effects, a detailed understanding of the interaction of melittin with membranes is crucial. We have investigated the interaction of melittin with membranes of varying surface charge in the context of recent studies which show that the presence of negatively charged lipids in the membrane inhibits membrane lysis by melittin. The sole tryptophan residue in melittin has previously been shown to be critical for its hemolytic activity. The organization and dynamics of the tryptophan residue thus become important to understand the peptide activity in membranes of different charge types. Wavelength-selective fluorescence was utilized to monitor the tryptophan environment of membrane-bound melittin. Melittin exhibits a red edge excitation shift (REES) of 5 nm when bound to zwitterionic membranes while in negatively charged membranes, the magnitude of REES is reduced to 2-3 nm. Further, wavelength dependence of fluorescence polarization and near-UV circular dichroism spectra reveal characteristic differences in the tryptophan environment for melittin bound to zwitterionic and anionic membranes. These studies are supported by time-resolved fluorescence measurements of membrane-bound melittin. Tryptophan penetration depths for melittin bound to zwitterionic and anionic membranes were analyzed by the parallax method [Chattopadhyay, A., and London, E. (1987) Biochemistry 26, 39-45] utilizing differential fluorescence quenching obtained with phospholipids spin-labeled at two different depths. Our results provide further insight into molecular details of membrane lysis by melittin and the modulation of lytic activity by negatively charged lipids.
Collapse
Affiliation(s)
- A K Ghosh
- Centre for Cellular and Molecular Biology, Hyderabad, India
| | | | | |
Collapse
|