缬氨霉素

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缬氨霉素
识别
CAS号 2001-95-8
ChemSpider 21493802
SMILES
InChI
InChIKey FCFNRCROJUBPLU-DNDCDFAIBE
ChEBI 28545
性质
化学式 C54H90N6O18
摩尔质量 1111.32 g·mol⁻¹
外观 白色固體
熔点 190 °C(463 K)
溶解性 甲醇、乙醇、乙酸乙酯、石油醚、二氯甲烷
λmax 220 nm
危险性
主要危害 Neurotoxicant
LD50 4 mg/kg (oral, rat)[2]
若非注明,所有数据均出自一般条件(25 ℃,100 kPa)下。

缬氨霉素Valinomycin)是一种抗生素

缬氨霉素是由數種鏈球菌細胞分離而得,像是S. tsusimaensis英语Streptomyces tsusimaensisS. fulvissimus英语Streptomyces fulvissimus

缬氨霉素會將鉀離子包住,使之疏水性大增,可以穿越細胞膜。[3]缬氨霉素-鉀離子複合物的平衡常數高達106,而相對的其鈉離子複合物的平衡常數僅有10。[4]這種差異造成其特殊的生理意義。

结构[编辑]

缬氨霉素是一種離子載體,因為他不帶有任何殘基電荷。它由重复三次的D-纈胺酸、L-纈胺酸、D-α-羟基异戊酸盐英语alpha-hydroxyisovaleric acid,和L-乳酸環狀結合,分子間彼此由胺基酯基結合。結構中的十二個羰基使他可以緊緊抓住中間的金屬離子,且可溶於極性溶劑當中,而當中的異丙基甲基則使之可溶於非極性溶劑當中[5]


且對於離子有高度選擇性,不會接受電性及化性相仿的離子[6]

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.

應用[编辑]

有研究指出缬氨霉素可能可以治療冠狀病毒感染Vero E6 cells英语所造成的急性呼吸道疾病。

缬氨霉素還可作為鉀離子選擇電極的易構重組劑。[7][8]

由於此物質為一種離子載體,可以在實驗中用於摧毀細胞的電位梯度[9]

外部連結[编辑]

參考文獻[编辑]

  1. ^ http://chem.sis.nlm.nih.gov/chemidplus/rn/2001-95-8
  2. ^ http://chem.sis.nlm.nih.gov/chemidplus/rn/2001-95-8
  3. ^ Cammann K. Ion-selective bulk membranes as models. Top. Curr. Chem. 1985年, 128: 219–258. 
  4. ^ Rose, M.C.; Henkens, R.W. Stability of sodium and potassium complexes of valinomycin. BBA. 1974年, 372 (2): 426–435. doi:10.1016/0304-4165(74)90204-9. 
  5. ^ Thompson M and Krull UJ. The electroanalytical response of the bilayer lipid membrane to valinomycin: membrane cholesterol content. Anal. Chim. Acta. 1982年, 141: 33–47. doi:10.1016/S0003-2670(01)95308-5. 
  6. ^ Rose, L; Jenkins, A. T. The effect of the ionophore valinomycin on biomimetic solid supported lipid DPPTE/EPC membranes. Bioelectrochemistry. 2007年, 70 (2): 387–93. doi:10.1016/j.bioelechem.2006.05.009. PMID 16875886.  编辑
  7. ^ Safiulina D, Veksler V, Zharkovsky A and Kaasik A. Loss of mitochondrial membrane potential is associated with increase in mitochondrial volume: physiological role in neurones. J. Cell. Physiol. 2006年, 206 (2): 347–353. doi:10.1002/jcp.20476. PMID 16110491. 
  8. ^ Potassium ionophore Bulletin
  9. ^ 1.File.tmp/k_potassium.pdf Potassium ionophore Bulletin]

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