1887

Chapter 13 : MscL, a Bacterial Mechanosensitive Channel

MyBook is a cheap paperback edition of the original book and will be sold at uniform, low price.

Ebook: Choose a downloadable PDF or ePub file. Chapter is a downloadable PDF file. File must be downloaded within 48 hours of purchase

Buy this Chapter
Digital (?) $15.00

Preview this chapter:
Zoom in
Zoomout

MscL, a Bacterial Mechanosensitive Channel, Page 1 of 2

| /docserver/preview/fulltext/10.1128/9781555816452/9781555813284_Chap13-1.gif /docserver/preview/fulltext/10.1128/9781555816452/9781555813284_Chap13-2.gif

Abstract:

This chapter discusses properties, structure, and the mechanism of gating of the large mechanosensitive (MS) channel MscL, which is probably the best understood tension-gated channel to date. The progress has been rapid, and within 10 years of MscL cloning we have a reasonably supported structural model of gating. The membrane topology determined with the PhoA fusion approach indicated that the short N-terminal (S1, ~15 residues) and the larger C-terminal (S3, ~40 residues) segments are cytoplasmic, whereas the loop connecting M1 and M2 segments (S2, ~25 residues) resides on the extracellular side (periplasm). MscL is activated directly by tension in the lipid bilayer in which the protein is embedded. Upon a strong osmotic downshift, hydrostatic pressure building up inside the cell causes a distension of the elastic cell wall and eventually stresses the inner membrane. Analysis of occupancies of substates and rates of subtransitions as functions of tension provided valuable information about the positions of intermediate states and major barriers on the reaction coordinate. MscL remains stable and functional in liposomes made of exogenous lipids. Initial characterization of MscL using scanning cysteine mutagenesis, site-specific spin labeling, and electron paramagnetic resonance (EPR) spectroscopy demonstrated that the transmembrane region of EcoMscL has essentially the same organization as TbMscL, validating the correctness of the homology-based alignment of the EcoMscL model. The hypothetical S1 bundle was proposed to act as the second gate because a poreoccluding element was needed to explain the postulated expanded low-conducting substate.

Citation: Sukharev S, Anishkin A, Chiang C, Betanzos M, Guy H. 2005. MscL, a Bacterial Mechanosensitive Channel, p 259-290. In Kubalski A, Martinac B (ed), Bacterial Ion Channels and Their Eukaryotic Homologs. ASM Press, Washington, DC. doi: 10.1128/9781555816452.ch13

Key Concept Ranking

Bacteria and Archaea
0.6035381
Atomic Force Microscopy
0.42378256
0.6035381
Highlighted Text: Show | Hide
Loading full text...

Full text loading...

Figures

Image of Figure 1.
Figure 1.

The (TbMscL) and (EcoMscL) MscL homologs. (A) Alignment of the two sequences indicates 37% identity (asterisks). Boxes denote the short N-terminal domain (S1), the first (M1) and second (M2) transmembrane domains, and the cytoplasmic helical domain (S3). The region of M1 forming the main gate is shaded in gray. The alignment is truncated at the end of EcoMscL; thus, 23 extra residues at the C-terminal segment of TbMscL are not shown. (B) The TbMscL crystal structure and the model of EcoMscL built by homology. Upper panels represent the views from the top (periplasm) and the bottom panels are the side views. One subunit in each structure is represented as striped rods to show the topology of the polypeptide comprising S1, periplasmic loop (S2), cytoplasmic domains (S3), and M2-S3 connecting linkers. As seen from the alignment, the loops as well as S2- M3 linkers are divergent in the two species, and the correspondence between the model and the crystal structure is best in the more conserved transmembrane part. The N-terminal domain and the C-terminal end of TbMscL were not fully resolved; thus the S1 of EcoMscL was modeled anew as a short bundle of amphipathic helices.

Citation: Sukharev S, Anishkin A, Chiang C, Betanzos M, Guy H. 2005. MscL, a Bacterial Mechanosensitive Channel, p 259-290. In Kubalski A, Martinac B (ed), Bacterial Ion Channels and Their Eukaryotic Homologs. ASM Press, Washington, DC. doi: 10.1128/9781555816452.ch13
Permissions and Reprints Request Permissions
Download as Powerpoint
Image of Figure 2.
Figure 2.

MscL activities and conduction states. (A) A portion of a typical current trace recorded at −20 mV with openings shown as upward transitions. Downward deflections from the fully open state represent short and long subconducting states. (B) Amplitude histogram based on a 5-min recording containing about 10 opening events. The histogram was fit with 11 gaussian peaks defining the amplitudes of the closed, fully open states, and nine intermediate levels. (C) The linear kinetic scheme aligned with the protein area scale chosen as a reaction coordinate. The positions of each conducting state and the main energy barrier were concluded from analyses of state occupancies and subtransition rates as a function of tension.

Citation: Sukharev S, Anishkin A, Chiang C, Betanzos M, Guy H. 2005. MscL, a Bacterial Mechanosensitive Channel, p 259-290. In Kubalski A, Martinac B (ed), Bacterial Ion Channels and Their Eukaryotic Homologs. ASM Press, Washington, DC. doi: 10.1128/9781555816452.ch13
Permissions and Reprints Request Permissions
Download as Powerpoint
Image of Figure 3.
Figure 3.

Transmembrane helices of MscL in the crystal-like closed conformation (center) and two possible pathways for channel expansion. The 10-helix barrel-stave model with 10 almost parallel helices all participating in pore lining is shown on the left. The alternative five-helix tilted model is shown on the right. The highly tilted arrangement permits a larger pore lined primarily by M1 helices.

Citation: Sukharev S, Anishkin A, Chiang C, Betanzos M, Guy H. 2005. MscL, a Bacterial Mechanosensitive Channel, p 259-290. In Kubalski A, Martinac B (ed), Bacterial Ion Channels and Their Eukaryotic Homologs. ASM Press, Washington, DC. doi: 10.1128/9781555816452.ch13
Permissions and Reprints Request Permissions
Download as Powerpoint
Image of Figure 4.
Figure 4.

The AFM image of the expanded conformation of MscL (A) next to the spacefilled “tilted” model of the open MscL (B). (C) Arrangement of helices with S3 domains separated. The AFM image is taken from , where the MscL homolog from serovar Typhimurium was studied in supported alkylsilane monolayers. Courtesy of Vladimir Tsukruk.

Citation: Sukharev S, Anishkin A, Chiang C, Betanzos M, Guy H. 2005. MscL, a Bacterial Mechanosensitive Channel, p 259-290. In Kubalski A, Martinac B (ed), Bacterial Ion Channels and Their Eukaryotic Homologs. ASM Press, Washington, DC. doi: 10.1128/9781555816452.ch13
Permissions and Reprints Request Permissions
Download as Powerpoint
Image of Figure 5.
Figure 5.

Schematic representations of the closed-(left) and open-state models (right) of the transmembrane barrel of EcoMscL. The helices are depicted as cylinders and positions of alpha-carbons of the pore-lining residues are shown as spheres. The closed-to-open transition in the SG model is accompanied by a relatively small (20 to 30°) counterclockwise rotation of M1, which does not change substantially the pore-exposed face of the helix.

Citation: Sukharev S, Anishkin A, Chiang C, Betanzos M, Guy H. 2005. MscL, a Bacterial Mechanosensitive Channel, p 259-290. In Kubalski A, Martinac B (ed), Bacterial Ion Channels and Their Eukaryotic Homologs. ASM Press, Washington, DC. doi: 10.1128/9781555816452.ch13
Permissions and Reprints Request Permissions
Download as Powerpoint

References

/content/book/10.1128/9781555816452.chap13
1. Ajouz, B.,, C. Berrier,, M. Besnard,, B. Martinac,, and A. Ghazi. 2000. Contributions of the different extramembranous domains of the mechanosensitive ion channel MscL to its response to membrane tension. J. Biol. Chem. 275:10151022.
2. Ajouz, B.,, C. Berrier,, A. Garrigues,, M. Besnard,, and A. Ghazi. 1998. Release of thioredoxin via the mechanosensitive channel MscL during osmotic downshock of Escherichia coli cells. J. Biol. Chem. 273:2667026674.
3. Anishkin, A.,, C.-S. Chiang,, and S. Sukharev. 2005. Gain-of-function mutations reveal expanded intermediate states and a sequential action of two gates in MscL. J. Gen. Physiol. 125:155170.
4. Anishkin, A.,, V. Gendel,, N. A. Sharifi,, C. S. Chiang,, L. Shirinian,, H. R. Guy,, and S. Sukharev. 2003. On the conformation of the COOH-terminal domain of the large mechanosensitive channel MscL. J. Gen. Physiol. 121:227244.
5. Arkin, I. T.,, S. I. Sukharev,, P. Blount,, C. Kung,, and A. T. Brunger. 1998. Helicity, membrane incorporation, orientation and thermal stability of the large conductance mechanosensitive ion channel from E. coli. Biochim. Biophys. Acta 1369:131140.
6. Bartlett, J. L.,, G. Levin,, and P. Blount. 2004. An in vivo assay identifies changes in residue accessibility on mechanosensitive channel gating. Proc. Natl. Acad. Sci. USA 101:1016110165.
7. Bass, R. B.,, P. Strop,, M. Barclay,, and D. C. Rees. 2002. Crystal structure of Escherichia coli MscS, a voltagemodulated and mechanosensitive channel. Science 298:15821587.
8. Batiza, A. F.,, M. M. Kuo,, K. Yoshimura,, and C. Kung. 2002. Gating the bacterial mechanosensitive channel MscL in vivo. Proc. Natl. Acad. Sci. USA 99:56435648.
9. Batiza, A. F.,, I. Rayment,, and C. Kung. 1999. Channel gate! Tension, leak and disclosure. Structure Fold. Des. 7:R99R103.
10. Berrier, C.,, M. Besnard,, B. Ajouz,, A. Coulombe,, and A. Ghazi. 1996. Multiple mechanosensitive ion channels from Escherichia coli, activated at different thresholds of applied pressure. J. Membr. Biol. 151:175187.
11. Berrier, C.,, A. Coulombe,, C. Houssin,, and A. Ghazi. 1989. A patch-clamp study of ion channels of inner and outer membranes and of contact zones of E. coli, fused into giant liposomes. Pressure-activated channels are localized in the inner membrane. FEBS Lett. 259:2732.
12. Betanzos, M.,, C. S. Chiang,, H. R. Guy,, and S. Sukharev. 2002. A large iris-like expansion of a mechanosensitive channel protein induced by membrane tension. Nat. Struct. Biol. 9:704710.
13. Bilston, L. E., and K. Mylvaganam. 2002. Molecular simulations of the large conductance mechanosensitive (MscL) channel under mechanical loading. FEBS Lett. 512:185190.
14. Blount, P.,, M. J. Schroeder,, and C. Kung. 1997. Mutations in a bacterial mechanosensitive channel change the cellular response to osmotic stress. J. Biol. Chem. 272:3215032157.
15. Blount, P.,, S. I. Sukharev,, P. C. Moe,, M. J. Schroeder,, H. R. Guy,, and C. Kung. 1996a. Membrane topology and multimeric structure of a mechanosensitive channel protein of Escherichia coli. EMBO J. 15:47984805.
16. Blount, P.,, S. I. Sukharev,, M. J. Schroeder,, S. K. Nagle,, and C. Kung. 1996b. Single residue substitutions that change the gating properties of a mechanosensitive channel in Escherichia coli. Proc. Natl. Acad. Sci. USA 93:1165211657.
17. Booth, I. R.,, and P. Louis. 1999. Managing hypoosmotic stress: aquaporins and mechanosensitive channels in Escherichia coli. Curr. Opin. Microbiol. 2:166169.
18. Chang, G.,, R. H. Spencer,, A. T. Lee,, M. T. Barclay,, and D. C. Rees. 1998. Structure of the MscL homolog from Mycobacterium tuberculosis: a gated mechanosensitive ion channel. Science 282:22202226.
19. Chiang, C. S.,, A. Anishkin,, and S. Sukharev. 2004a. Gating of the large mechanosensitive channel in situ: estimation of the spatial scale of the transition from channel population responses. Biophys. J. 86:28462861.
20. Chiang, C.-S.,, L. Shirinian,, and S. Sukharev. 2004b. Capping transmembrane helices of the mechanosensitive channel MscL with aromatic residues changes its sensitivity to stretch. Biophys. J. 86:546a.
21. Clapham, D. E. 2003. TRP channels as cellular sensors. Nature 426:517524.
22. Clayton, D.,, G. Shapovalov,, J. A. Maurer,, D. A. Dougherty,, H. A. Lester,, and G. G. Kochendoerfer. 2004. Total chemical synthesis and electrophysiological characterization of mechanosensitive channels from Escherichia coli and Mycobacterium tuberculosis. Proc. Natl. Acad. Sci. USA 101:47644769.
23. Colbert, H. A.,, T. L. Smith,, and C. I. Bargmann. 1997. OSM-9, a novel protein with structural similarity to channels, is required for olfaction, mechanosensation, and olfactory adaptation in Caenorhabditis elegans. J. Neurosci. 17:82598269.
24. Colombo, G.,, S. J. Marrink,, and A. E. Mark. 2003. Simulation of MscL gating in a bilayer under stress. Biophys. J. 84:23312337.
25. Corey, D. P. 2003. New TRP channels in hearing and mechanosensation. Neuron 39:585588.
26. Criado, M.,, and B. U. Keller. 1987. A membrane fusion strategy for single-channel recordings of membranes usually non-accessible to patch-clamp pipette electrodes. FEBS Lett. 224:172176.
27. Cruickshank, C. C.,, R. F. Minchin,, A. C. Le Dain,, and B. Martinac. 1997. Estimation of the pore size of the large-conductance mechanosensitive ion channel of Escherichia coli. Biophys. J. 73:19251931.
28. Cui, C.,, and J. Adler. 1996. Effect of mutation of potassium-efflux system, KefA, on mechanosensitive channels in the cytoplasmic membrane of Escherichia coli. J. Membr. Biol. 150:143152.
29. Cui, C.,, D. O. Smith,, and J. Adler. 1995. Characterization of mechanosensitive channels in Escherichia coli cytoplasmic membrane by whole-cell patch clamp recording. J. Membr. Biol. 144:3142.
30. Delcour, A. H.,, B. Martinac,, J. Adler,, and C. Kung. 1989. Modified reconstitution method used in patch-clamp studies of Escherichia coli ion channels. Biophys. J. 56:631636.
31. Elmore, D. E.,, and D. A. Dougherty. 2001. Molecular dynamics simulations of wild-type and mutant forms of the Mycobacterium tuberculosis MscL channel. Biophys. J. 81:13451359.
32. Elmore, D. E.,, and D. A. Dougherty. 2003. Investigating lipid composition effects on the mechanosensitive channel of large conductance (MscL) using molecular dynamics simulations. Biophys. J. 85:15121524.
33. Gillespie, P. G.,, and R. G. Walker. 2001. Molecular basis of mechanosensory transduction. Nature 413:194202.
34. Gullingsrud, J.,, D. Kosztin,, and K. Schulten. 2001. Structural determinants of MscL gating studied by molecular dynamics simulations. Biophys. J. 80:20742081.
35. Gullingsrud, J.,, and K. Schulten. 2003. Gating of MscL studied by steered molecular dynamics. Biophys. J. 85:20872099.
36. Gullingsrud, J.,, and K. Schulten. 2004. Lipid bilayer pressure profiles and mechanosensitive channel gating. Biophys. J. 86:34963509.
37. Hamill, O. P.,, and B. Martinac. 2001. Molecular basis of mechanotransduction in living cells. Physiol. Rev. 81:685740.
38. Hamill, O. P.,, A. Marty,, E. Neher,, B. Sakmann,, and F. J. Sigworth. 1981. Improved patch-clamp techniques for high-resolution current recording from cells and cell-free membrane patches. Pflugers Arch. 391:85100.
39. Hase, C. C.,, A. C. Le Dain,, and B. Martinac. 1995. Purification and functional reconstitution of the recombinant large mechanosensitive ion channel (MscL) of Escherichia coli. J. Biol. Chem. 270:1832918334.
40. Hase, C. C.,, A. C. Le Dain,, and B. Martinac. 1997. Molecular dissection of the large mechanosensitive ion channel (MscL) of E. coli: mutants with altered channel gating and pressure sensitivity. J. Membr. Biol. 157:1725.
41. Howard, J.,, W. M. Roberts,, and A. J. Hudspeth. 1988. Mechanoelectrical transduction by hair cells. Annu. Rev. Biophys. Biophys. Chem. 17:99124.
42. Ingber, D. E. 2003. Tensegrity I. Cell structure and hierarchical systems biology. J. Cell Sci. 116:11571173.
43. Iscla, I.,, G. Levin,, R. Wray,, R. Reynolds,, and P. Blount. 2004. Defining the physical gate of a mechanosensitive channel, MscL, by engineering metal-binding sites. Biophys. J. 87:31723180.
44. Karlin, A.,, and M. H. Akabas. 1998. Substituted-cysteine accessibility method. Methods Enzymol. 293:123145.
45. Kelly, B. L.,, and A. Gross. 2003. Potassium channel gating observed with site-directed mass tagging. Nat. Struct. Biol. 10:280284.
46. Kloda, A.,, and B. Martinac. 2001. Mechanosensitive channels in archaea. Cell Biochem. Biophys. 34: 349381.
47. Kong, Y.,, Y. Shen,, T. E. Warth,, and J. Ma. 2002. Conformational pathways in the gating of Escherichia coli mechanosensitive channel. Proc. Natl. Acad. Sci. USA 99:59996004.
48. Koprowski, P.,, and A. Kubalski. 2001. Bacterial ion channels and their eukaryotic homologues. Bioessays 23:11481158.
49. Levin, G.,, and P. Blount. 2004. Cysteine scanning of MscL transmembrane domains reveals residues critical for mechanosensitive channel gating. Biophys. J. 86:28622870.
50. Levina, N.,, S. Totemeyer,, N. R. Stokes,, P. Louis,, M. A. Jones,, and I. R. Booth. 1999. Protection of Escherichia coli cells against extreme turgor by activation of MscS and MscL mechanosensitive channels: identification of genes required for MscS activity. EMBO J. 18:17301737.
51. Li, Y.,, R. Wray,, and P. Blount. 2004. Intragenic suppression of gain-of-function mutations in the Escherichia coli mechanosensitive channel, MscL. Mol. Microbiol. 53:485495.
52. Liu, W.,, W. Dietmer,, and B. Martinac. 1999. Glycine G14, the amino acid essential for electromechanical coupling in gating the MscL of E. coli by mechanical force. Biophys. J. 76:A203.
53. Malashkevich, V. N.,, R. A. Kammerer,, V. P. Efimov,, T. Schulthess,, and J. Engel. 1996. The crystal structure of a five-stranded coiled coil in COMP: a prototype ion channel? Science 274:761765.
54. Martinac, B.,, J. Adler,, and C. Kung. 1990. Mechanosensitive ion channels of E. coli activated by amphipaths. Nature 348:261263.
55. Martinac, B.,, M. Buechner,, A. H. Delcour,, J. Adler,, and C. Kung. 1987. Pressure-sensitive ion channel in Escherichia coli. Proc. Natl. Acad. Sci. USA 84:22972301.
56. Martinac, B.,, D. M. Cortes,, and E. Perozo. 2004. Structural dynamics of MscL C-terminal domain. Biophys. J. 86:547a.
57. Maurer, J. A., and D. A. Dougherty. 2001. A high-throughput screen for MscL channel activity and mutational phenotyping. Biochim. Biophys. Acta 1514:165169.
58. Maurer, J. A.,, and D. A. Dougherty. 2003. Generation and evaluation of a large mutational library from the Escherichia coli mechanosensitive channel of large conductance, MscL: implications for channel gating and evolutionary design. J. Biol. Chem. 278:2107621082.
59. Maurer, J. A.,, D. E. Elmore,, H. A. Lester,, and D. A. Dougherty. 2000. Comparing and contrasting Escherichia coli and Mycobacterium tuberculosis mechanosensitive channels (MscL). New gain of function mutations in the loop region. J. Biol. Chem. 275:2223822244.
60. Mitchell, P. 1979. Keilin’s respiratory chain concept and its chemiosmotic consequences. Science 206:11481159.
61. Moe, P. C.,, P. Blount,, and C. Kung. 1998. Functional and structural conservation in the mechanosensitive channel MscL implicates elements crucial for mechanosensation. Mol. Microbiol. 28:583592.
62. Moe, P. C.,, G. Levin,, and P. Blount. 2000. Correlating a protein structure with function of a bacterial mechanosensitive channel. J. Biol. Chem. 275:3112131127.
63. Nakamaru, Y.,, Y. Takahashi,, T. Unemoto,, and T. Nakamura. 1999. Mechanosensitive channel functions to alleviate the cell lysis of marine bacterium, Vibrio alginolyticus, by osmotic downshock. FEBS Lett. 444: 170172.
64. Naruse, K.,, Q. Tang,, Q. Zhi,, and M. Sokabe. 2003. Cloning and functional expression of a stretch-activated BK channel (SAKCa) from chick embryonic cardiomyocyte. Biophys. J. 84:234a.
65. Oakley, A. J.,, B. Martinac,, and M. C. Wilce. 1999. Structure and function of the bacterial mechanosensitive channel of large conductance. Protein Sci. 8:19151921.
66. Olbrich, K.,, W. Rawicz,, D. Needham,, and E. Evans. 2000. Water permeability and mechanical strength of polyunsaturated lipid bilayers. Biophys. J. 79:321327.
67. Ornatska, M.,, S. E. Jones,, R. R. Naik,, M. O. Stone,, and V. V. Tsukruk. 2003. Biomolecular stress-sensitive gauges: surface-mediated immobilization of mechanosensitive membrane protein. J. Am. Chem. Soc. 125: 1272212723.
68. Ou, X.,, P. Blount,, R. J. Hoffman,, and C. Kung. 1998. One face of a transmembrane helix is crucial in mechanosensitive channel gating. Proc. Natl. Acad. Sci. USA 95:1147111475.
69. Park, K. H.,, C. Berrier,, B. Martinac,, and A. Ghazi. 2004. Purification and functional reconstitution of N- and C-halves of the MscL channel. Biophys. J. 86:21292136.
70. Patapoutian, A.,, A. M. Peier,, G. M. Story,, and V. Viswanath. 2003. ThermoTRP channels and beyond: mechanisms of temperature sensation. Nat. Rev. Neurosci. 4:529539.
71. Patel, A. J.,, and E. Honore. 2001. Properties and modulation of mammalian 2P domain K+ channels. Trends Neurosci. 24:339346.
72. Perozo, E.,, D. M. Cortes,, P. Sompornpisut,, A. Kloda,, and B. Martinac. 2002a. Open channel structure of MscL and the gating mechanism of mechanosensitive channels. Nature 418:942948.
73. Perozo, E.,, A. Kloda,, D. M. Cortes,, and B. Martinac. 2001. Site-directed spin-labeling analysis of reconstituted MscL in the closed state. J. Gen. Physiol. 118:193206.
74. Perozo, E.,, A. Kloda,, D. M. Cortes,, and B. Martinac. 2002b. Physical principles underlying the transduction of bilayer deformation forces during mechanosensitive channel gating. Nat. Struct. Biol. 9:696703.
75. Perozo, E.,, and D. C. Rees. 2003. Structure and mechanism in prokaryotic mechanosensitive channels. Curr. Opin. Struct. Biol. 13:432442.
76. Pivetti, C. D.,, M. R. Yen,, S. Miller,, W. Busch,, Y. H. Tseng,, I. R. Booth,, and M. H. Saier, Jr. 2003. Two families of mechanosensitive channel proteins. Microbiol. Mol. Biol. Rev. 67:6685.
77. Ruthe, H. J.,, and J. Adler. 1985. Fusion of bacterial spheroplasts by electric fields. Biochim. Biophys. Acta 819:105113.
78. Sachs, F. 1992. Stretch-sensitive ion channels: an update. Soc. Gen. Physiol. Ser. 47:241260.
79. Sachs, F.,, and C. E. Morris. 1998. Mechanosensitive ion channels in nonspecialized cells. Rev. Physiol. Biochem. Pharmacol. 132:177.
80. Saint, N.,, J. J. Lacapere,, L. Q. Gu,, A. Ghazi,, B. Martinac,, and J. L. Rigaud. 1998. A hexameric transmembrane pore revealed by two-dimensional crystallization of the large mechanosensitive ion channel (MscL) of Escherichia coli. J. Biol. Chem. 273:1466714670.
81. Sali, A.,, L. Potterton,, F. Yuan,, H. van Vlijmen,, and M. Karplus. 1995. Evaluation of comparative protein modeling by MODELLER. Proteins 23:318326.
82. Shapovalov, G.,, R. Bass,, D. C. Rees,, and H. A. Lester. 2003. Open-state disulfide crosslinking between Mycobacterium tuberculosis mechanosensitive channel subunits. Biophys. J. 84:23572365.
83. Shapovalov, G.,, and H. A. Lester. 2004. Gating transitions in bacterial ion channels measured at 3 microns resolution. J. Gen. Physiol. 124:151161.
84. Spencer, R. H.,, G. Chang,, and D. C. Rees. 1999. ‘Feeling the pressure’: structural insights into a gated mechanosensitive channel. Curr. Opin. Struct. Biol. 9:448-454. (Erratum, 9:650651.)
85. Spencer, R. H.,, and D. C. Rees. 2002. The alpha-helix and the organization and gating of channels. Annu. Rev. Biophys. Biomol. Struct. 31:207233.
86. Sukharev, S. 2002. Purification of the small mechanosensitive channel of Escherichia coli (MscS): the subunit structure, conduction, and gating characteristics in liposomes. Biophys. J. 83:290298.
87. Sukharev, S.,, M. Betanzos,, C. S. Chiang,, and H. R. Guy. 2001a. The gating mechanism of the large mechanosensitive channel MscL. Nature 409:720724.
88. Sukharev, S.,, and D. P. Corey. 2004. Mechanosensitive channels: multiplicity of families and gating paradigms. Sci. STKE 2004:re4.
89. Sukharev, S.,, S. R. Durell,, and H. R. Guy. 2001b. Structural models of the MscL gating mechanism. Biophys. J. 81:917936.
90. Sukharev, S. I.,, P. Blount,, B. Martinac,, F. R. Blattner,, and C. Kung. 1994a. A large-conductance mechanosensitive channel in E. coli encoded by MscL alone. Nature 368:265268.
91. Sukharev, S. I.,, B. Martinac,, V. Y. Arshavsky,, and C. Kung. 1993. Two types of mechanosensitive channels in the Escherichia coli cell envelope: solubilization and functional reconstitution. Biophys. J. 65: 177183.
92. Sukharev, S. I.,, B. Martinac,, P. Blount,, and C. Kung. 1994b. Functional reconstitution as an assay for biochemical isolation of channel proteins: application to the molecular identification of a bacterial mechanosensitive channel. Methods Companion Methods Enzymol. 6:5159.
93. Sukharev, S. I.,, M. J. Schroeder,, and D. R. McCaslin. 1999a. Stoichiometry of the large conductance bacterial mechanosensitive channel of E. coli. A biochemical study. J. Membr. Biol. 171:183193.
94. Sukharev, S. I.,, W. J. Sigurdson,, C. Kung,, and F. Sachs. 1999b. Energetic and spatial parameters for gating of the bacterial large conductance mechanosensitive channel, MscL. J. Gen. Physiol. 113:525540.
95. Szabo, I.,, V. Petronilli,, and M. Zoratti. 1993. A patch-clamp investigation of the Streptococcus faecalis cell membrane. J. Membr. Biol. 131:203218.
96. Tank, D. W.,, C. Miller,, and W. W. Webb. 1982. Isolated-patch recording from liposomes containing functionally reconstituted chloride channels from Torpedo electroplax. Proc. Natl. Acad. Sci. USA 79: 77497753.
97. Tavernarakis, N.,, and M. Driscoll. 1997. Molecular modeling of mechanotransduction in the nematode Caenorhabditis elegans. Annu. Rev. Physiol. 59:659689.
98. Valadie, H.,, J. J. Lacapcre,, Y. H. Sanejouand,, and C. Etchebest. 2003. Dynamical properties of the MscL of Escherichia coli: a normal mode analysis. J. Mol. Biol. 332:657674.
99. Van Wagoner, D. R. 1993. Mechanosensitive gating of atrial ATP-sensitive potassium channels. Circ. Res. 72:973983.
100. Vazquez-Laslop, N.,, H. Lee,, R. Hu,, and A. A. Neyfakh. 2001. Molecular sieve mechanism of selective release of cytoplasmic proteins by osmotically shocked Escherichia coli. J. Bacteriol. 183:23992404.
101. Welsh, M. J.,, M. P. Price,, and J. Xie. 2002. Biochemical basis of touch perception: mechanosensory function of degenerin/epithelial Na+ channels. J. Biol. Chem. 277:23692372.
102. White, S. H.,, and W. C. Wimley. 1999. Membrane protein folding and stability: physical principles. Annu. Rev. Biophys. Biomol. Struct. 28:319365.
103. Wiggins, P.,, and R. Phillips. 2004. Analytic models for mechanotransduction: gating a mechanosensitive channel. Proc. Natl. Acad. Sci. USA 101:40714076.
104. Wood, J. M. 1999. Osmosensing by bacteria: signals and membrane-based sensors. Microbiol. Mol. Biol. Rev. 63:230262.
105. Yoshimura, K.,, A. Batiza,, and C. Kung. 2001. Chemically charging the pore constriction opens the mechanosensitive channel MscL. Biophys. J. 80:21982206.
106. Yoshimura, K.,, A. Batiza,, M. Schroeder,, P. Blount,, and C. Kung. 1999. Hydrophilicity of a single residue within MscL correlates with increased channel mechanosensitivity. Biophys. J. 77:19601972.
107. Yoshimura, K.,, T. Nomura,, and M. Sokabe. 2004. Loss-of-function mutations at the rim of the funnel of mechanosensitive channel MscL. Biophys. J. 86:21132120.
108. Zoratti, M.,, and V. Petronilli. 1988. Ion-conducting channels in a gram-positive bacterium. FEBS Lett. 240:105109.
109. Zoratti, M.,, V. Petronilli,, and I. Szabo. 1990. Stretch-activated composite ion channels in Bacillus subtilis. Biochem. Biophys. Res. Commun. 168:443450.

This is a required field
Please enter a valid email address
Please check the format of the address you have entered.
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error