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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/07/22 18:53:02」(JST)

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Valinomycin is a dodecadepsipeptide antibiotic.

Valinomycin is obtained from the cells of several Streptomyces strains, among which "S. tsusimaensis" and S. fulvissimus.

It is a member of the group of natural neutral ionophores because it does not have a residual charge. It consists of enantiomers D- and L-valine (Val), D-alpha-hydroxyisovaleric acid and L-lactic acid. Structures are alternately bound via amide and ester bridges. Valinomycin is highly selective for potassium ions over sodium ions within the cell membrane.^[1] It functions as a potassium-specific transporter and facilitates the movement of potassium ions through lipid membranes "down" an electrochemical potential gradient.^[2] The stability constant K for the potassium-valinomycin complex is 10⁶ and for the sodium-valinomycin complex only 10.^[3] This difference is important for maintaining the selectivity of valinomycin for the transport of potassium ions (and not sodium ions) in biological systems.

Structure

Valinomycin is a dodecadepsipeptide, that is, it is made of twelve alternating amino acids and esters to form a macrocyclic molecule. The twelve carbonyl groups are essential for the binding of metal ions, and also for solvation in polar solvent. The isopropyl and methyl groups are responsible for solvation in nonpolar solvents. ^[4] Along with its shape and size this molecular duality is the main reason for its binding properties. K ions must give up their water of hydration to pass through the pore. K⁺ ions are octahedrally coordinated in a square bipyramidal geometry by 6 carbonyl bonds from Val. In this space of 1.33 Angstrom, Na⁺ with its 0.95 Angstrom radius, is significantly smaller than the channel, meaning that Na⁺ cannot form ionic bonds with the amino acids of the pore at equivalent energy as those it gives up with the water molecules. This leads to a 10,000x selectivity for K⁺ ions over Na⁺. For polar solvents, valinomycin will mainly expose the carbonyls to the solvent and in nonpolar solvents the isopropyl groups are located predominantly on the exterior of the molecule. This conformation changes when valinomycin is bound to a potassium ion. The molecule is "locked" into a conformation with the isopropyl groups on the exterior. It is not actually locked into configuration because the size of the molecule makes it highly flexible, but the potassium ion gives some degree of coordination to the macromolecule.

Applications

Valinomycin was recently reported to be the most potent agent against severe acute respiratory-syndrome coronavirus (SARS-CoV) in infected Vero E6 cells.

Valinomycin acts as a nonmetallic isoforming agent in potassium selective electrodes.^[5]^[6]

This ionophore is also used in experiments with membrane vesicles to destroy the electrochemical gradient, if such is required by the design of the experiment. ^[7]

References

^ Lars, Rose; Jenkins ATA, (2007). "The effect of the ionophore valinomycin on biomimetic solid supported lipid DPPTE/EPC membranes". Bioelectrochem. 70 (2): 387–393. doi:10.1016/j.bioelechem.2006.05.009. PMID 16875886.
^ Cammann K (1985). "Ion-selective bulk membranes as models". Top. Curr. Chem. 128: 219–258.
^ Rose, M.C.; Henkens, R.W. (1974). "Stability of sodium and potassium complexes of valinomycin". BBA 372 (2): 426–435. doi:10.1016/0304-4165(74)90204-9. Cite uses deprecated parameters (help)
^ Thompson M and Krull UJ (1982). "The electroanalytical response of the bilayer lipid membrane to valinomycin: membrane cholesterol content". Anal. Chim. Acta 141: 33–47. doi:10.1016/S0003-2670(01)95308-5.
^ Safiulina D, Veksler V, Zharkovsky A and Kaasik A (2006). "Loss of mitochondrial membrane potential is associated with increase in mitochondrial volume: physiological role in neurones". J. Cell. Physiol. 206 (2): 347–353. doi:10.1002/jcp.20476. PMID 16110491.
^ Potassium ionophore Bulletin
^ 1.File.tmp/k_potassium.pdf Potassium ionophore Bulletin]

External links

Chemical Safety Regulations from New Jersey Department of Health.
Health information on Scorecard.
Valinomycin from Fermentek.
Pesticide Properties DataBase (PPDB) record for Valinomycin

English Journal

All-solid-state selective electrodes using carbon black.

Paczosa-Bator B.SourceAGH University of Science and Technology, Faculty of Material Science and Ceramics, Mickiewicza 30, PL-30059 Cracow, Poland.
Talanta.Talanta.2012 May 15;93:424-7. Epub 2012 Feb 11.
This study developed new types of all-solid-state ion-selective electrodes based on carbon black (CB). The electrodes were obtained basing on two methods. The first method concerned the addition of the CB as an intermediate layer between an ionophore-doped solvent polymeric membrane and an electrica
PMID 22483932

Natural compounds inhibiting the replication of Porcine reproductive and respiratory syndrome virus.

Karuppannan AK, Wu KX, Qiang J, Chu JJ, Kwang J.SourceAnimal Health Biotechnology Group, Temasek Lifesciences Laboratory, National University of Singapore, 1 Research Link, Singapore 117604, Singapore.
Antiviral research.Antiviral Res.2012 May;94(2):188-94. Epub 2012 Apr 3.
Porcine reproductive and respiratory syndrome virus (PRRSV) is an economically important pathogenic virus in the swine production. Current vaccines against PRRSV do not induce sterile immunity and the virus evolves at a rapid rate with frequent appearances of new strains. In this study, we screened
PMID 22487208

Japanese Journal

LC-MS/MSによる穀物加工食品および粉ミルク中のセレウリドの分析法

八津川洋一,飯田華子,永田和子 [他]
食品衛生学雑誌 52(5), 287-293, 2011-10
NAID 40019046133

Oxalate efflux transporter from the brown rot fungus Fomitopsis palustris.

Watanabe Tomoki,Shitan Nobukazu,Suzuki Shiro,Umezawa Toshiaki,Shimada Mikio,Yazaki Kazufumi,Hattori Takefumi
Applied and environmental microbiology 76(23), 7683-7690, 2010-12
… palustris was ATP dependent and was strongly inhibited by several inhibitors, such as valinomycin and NH(4)(+), suggesting the presence of a secondary oxalate transporter in this fungus. …
NAID 120002723134

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Valinomycin
Identifiers
CAS number	2001-95-8
ChemSpider	21493802
ChEBI	CHEBI:28545
ChEMBL	CHEMBL216815
Jmol-3D images	Image 1
	SMILES CC1C(=O)NC(C(=O)OC(C(=O)NC(C(=O)OC(C(=O)NC(C(=O)OC(C(=O)NC(C(=O)OC(C(=O)NC(C(=O)OC(C(=O)NC(C(=O)O1)C(C)C)C(C)C)C(C)C)C)C(C)C)C(C)C)C(C)C)C)C(C)C)C(C)C)C(C)C ;
	InChI InChI=1S/C54H90N6O18/c1-22(2)34-49(67)73-31(19)43(61)55-38(26(9)10)53(71)77-41(29(15)16)47(65)59-36(24(5)6)51(69)75-33(21)45(63)57-39(27(11)12)54(72)78-42(30(17)18)48(66)60-35(23(3)4)50(68)74-32(20)44(62)56-37(25(7)8)52(70)76-40(28(13)14)46(64)58-34/h22-42H,1-21H3,(H,55,61)(H,56,62)(H,57,63)(H,58,64)(H,59,65)(H,60,66)/t31-,32-,33-,34+,35+,36+,37-,38-,39-,40+,41+,42+/m0/s1 ; Key: FCFNRCROJUBPLU-DNDCDFAISA-N InChI=1/C54H90N6O18/c1-22(2)34-49(67)73-31(19)43(61)55-38(26(9)10)53(71)77-41(29(15)16)47(65)59-36(24(5)6)51(69)75-33(21)45(63)57-39(27(11)12)54(72)78-42(30(17)18)48(66)60-35(23(3)4)50(68)74-32(20)44(62)56-37(25(7)8)52(70)76-40(28(13)14)46(64)58-34/h22-42H,1-21H3,(H,55,61)(H,56,62)(H,57,63)(H,58,64)(H,59,65)(H,60,66)/t31-,32-,33-,34+,35+,36+,37-,38-,39-,40+,41+,42+/m0/s1; Key: FCFNRCROJUBPLU-DNDCDFAIBE ;
Properties
Molecular formula	C54H90N6O18
Molar mass	1111.32
Appearance	White solid
Melting point	172°C –177 °C
Solubility	Methanol, ethanol, ethyl acetate, petrol-ether, dichloromethane
λmax	220 nm
Hazards
Main hazards	Neurotoxicant
	Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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	Infobox references

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英: valinomycin
関: イオノフォア

ペプチド系抗生物質;K+イオノフォア

[1] Lars, Rose; Jenkins ATA, (2007). "The effect of the ionophore valinomycin on biomimetic solid supported lipid DPPTE/EPC membranes". Bioelectrochem. 70 (2): 387–393. doi:10.1016/j.bioelechem.2006.05.009. PMID 16875886.

[2] Cammann K (1985). "Ion-selective bulk membranes as models". Top. Curr. Chem. 128: 219–258.

[3] Rose, M.C.; Henkens, R.W. (1974). "Stability of sodium and potassium complexes of valinomycin". BBA 372 (2): 426–435. doi:10.1016/0304-4165(74)90204-9. Cite uses deprecated parameters (help)

[4] Thompson M and Krull UJ (1982). "The electroanalytical response of the bilayer lipid membrane to valinomycin: membrane cholesterol content". Anal. Chim. Acta 141: 33–47. doi:10.1016/S0003-2670(01)95308-5.

[5] Safiulina D, Veksler V, Zharkovsky A and Kaasik A (2006). "Loss of mitochondrial membrane potential is associated with increase in mitochondrial volume: physiological role in neurones". J. Cell. Physiol. 206 (2): 347–353. doi:10.1002/jcp.20476. PMID 16110491.

[6] Potassium ionophore Bulletin

[7] 1.File.tmp/k_potassium.pdf Potassium ionophore Bulletin]

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valinomycin