编辑“︁G418”︁

{{About|抗生素|高铁列车车次|邕港高速动车组列车}}
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| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 461115152
| ImageFile = G418.svg
| ImageSize = 160
| IUPACName = (2''R'',3''S'',4''R'',5''R'',6''S'')-5-Amino-6-[(1''R'',2''S'',3''S'',4''R'',6''S'')-4,6-diamino-3-[(2''R'',3''R'',4''R'',5''R'')-3,5-dihydroxy-5-methyl-4-methylaminooxan-2-yl]oxy-2-hydroxycyclohexyl]oxy-
2-(1-hydroxyethyl)oxane-3,4-diol
| SystematicName = 
| OtherNames = 遺傳黴素<br>''O''-2-Amino-2,7-didesoxy-<small>D</small>-glycero-α-<small>D</small>-gluco-heptopyranosyl-(1→4)-''O''-(3-desoxy-4-''C''-methyl-3-(methylamino)-β-<small>L</small>-arabinopyranosyl- (1→6))-<small>D</small>-streptamin
|Section1={{Chembox Identifiers
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| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 21106441
| ChEMBL_Ref = {{ebicite|changed|EBI}}
| ChEMBL = 215226
| InChI = 1/C20H40N4O10/c1-6(25)14-11(27)10(26)9(23)18(32-14)33-15-7(21)4-8(22)16(12(15)28)34-19-13(29)17(24-3)20(2,30)5-31-19/h6-19,24-30H,4-5,21-23H2,1-3H3/t6-,7-,8+,9+,10+,11-,12-,13+,14?,15+,16-,17+,18+,19+,20-/m0/s1
| InChIKey = BRZYSWJRSDMWLG-NQRKCNNJBI
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/C20H40N4O10/c1-6(25)14-11(27)10(26)9(23)18(32-14)33-15-7(21)4-8(22)16(12(15)28)34-19-13(29)17(24-3)20(2,30)5-31-19/h6-19,24-30H,4-5,21-23H2,1-3H3/t6-,7-,8+,9+,10+,11-,12-,13+,14?,15+,16-,17+,18+,19+,20-/m0/s1
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = BRZYSWJRSDMWLG-NQRKCNNJSA-N
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo = 49863-47-0
| EINECS = 
| PubChem = 123865
| DrugBank_Ref = {{drugbankcite|correct|drugbank}}
| DrugBank = DB04263
| SMILES = O[C@H]3[C@H](O)[C@@H](N)[C@@H](O[C@@H]2[C@@H](N)C[C@@H](N)[C@H](O[C@H]1OC[C@](C)(O)[C@H](NC)[C@H]1O)[C@H]2O)OC3[C@@H](O)C
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| ChEBI_Ref = {{ebicite|correct|EBI}}
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| KEGG_Ref = {{keggcite|correct|kegg}}
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}}
|Section2={{Chembox Properties
| C=20 | H=40 | N=4 | O=10
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| Solubility = 50&nbsp;mg/mL
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|Section6={{Chembox Explosive
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|Section8={{Chembox Related
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}}
'''G418'''，即'''遺傳黴素'''（Geneticin），是一種[[氨基糖苷類抗生素]]，結構與慶大黴素B1相似。G418最初是於[[細菌]]{{link-en|小单孢菌|Micromonospora}}中發現<ref name=In>{{cite web|title=Geneticin|url=https://www.thermofisher.com/us/en/home/life-science/cell-culture/transfection/selection/g418.html|work=Thermo Fisher Scientific|accessdate=2017-11-29|archive-date=2017-08-08|archive-url=https://web.archive.org/web/20170808034522/https://www.thermofisher.com/us/en/home/life-science/cell-culture/transfection/selection/g418.html|dead-url=no}}</ref>。G418是[[新黴素]]的類似物，其作用機理也與新黴素相似。即，G418可以通過阻斷[[轉譯|多肽合成（蛋白轉譯）]]殺死[[原核細胞]]或[[真核細胞]]<ref name=In />。新黴素抗性基因''neo''可以編碼一種能使G418失效的酶{{link-en|氨基糖苷3'磷酸转移酶|aminoglycoside-3’-phosphotransferase}}，進而使細胞獲得對G418的抗性<ref name=In />。在實驗室中，利用上述機制，可以使用G418篩選[[基因工程]]改造後的細胞<ref>{{cite web|url=http://www.exactantigen.com/review/G418.html|title=G418|accessdate=2010-01-09|work=labome.com|deadurl=yes|archiveurl=https://web.archive.org/web/20091229191551/http://www.exactantigen.com/review/G418.html|archivedate=2009-12-29}}</ref>。

==作用機理及抗性機理==
G418是一種特殊的[[抗生素]]。G418既可以殺死[[真核細胞]]，也可以殺死[[原核細胞]]。G418的作用機理是通過與[[核糖體|80S核糖體]]（真核細胞）或70S核糖體（原核細胞）結合，進而阻止蛋白轉譯過程中的延長過程，使合成中的多肽鏈合成中止。最終，細胞會因爲缺乏必要的蛋白而死亡<ref>{{cite web|url=https://www.promega.com/-/media/files/resources/technical-references/antibiotic-mode-of-action.pdf|title=Antibiotics: Mode of Action and Mechanism of Resistance.|publisher=Promega|accessdate=2017-11-29|archive-date=2017-12-01|archive-url=https://web.archive.org/web/20171201032931/https://www.promega.com/-/media/files/resources/technical-references/antibiotic-mode-of-action.pdf|dead-url=no}}</ref><ref>{{cite web|url=http://www.invivogen.com/PDF/G418_TDS.pdf|title=G418 manual|publisher=invivogen|accessdate=2017-11-29|archive-date=2018-01-27|archive-url=https://web.archive.org/web/20180127124021/http://www.invivogen.com/PDF/G418_TDS.pdf|dead-url=no}}</ref>。基於G418的作用機理，對蛋白質需求較高的細胞，如分裂中的細胞，會比對蛋白質需求相對較少的細胞更快被G418殺死<ref>{{cite web|url=http://www.invivogen.com/g418|title=G418 introduction|publisher=invivogene|accessdate=2017-11-29|archive-date=2017-11-19|archive-url=https://web.archive.org/web/20171119060044/http://www.invivogen.com/g418|dead-url=no}}</ref>。新黴素抗性基因''neo''可以使細胞在含有G418的培養基中存活。''neo''基因抵抗G418的機理在於，neo基因能編碼一種{{link-en|氨基糖苷3'磷酸转移酶|aminoglycoside-3’-phosphotransferase}}。該酶可使G418磷酸化，減小其與核糖體的親和力，達到讓G418失效的作用<ref name="Kotra 2000">{{cite journal|title=Aminoglycosides: Perspectives on Mechanisms of Action and Resistance and Strategies to Counter Resistance |url=https://archive.org/details/sim_antimicrobial-agents-and-chemotherapy_2000-12_44_12/page/3249 |authors=Kotra, LP, Haddad J, Mobashery, S|PMID= 11083623|year=2000|PMC=90188|journal=Antimicrobial Agents and Chemotherapy|volume=44|issue=12|pages=3249–56|doi=10.1128/aac.44.12.3249-3256.2000}}</ref>。

==細胞生物學中的應用==
導入''neo''基因等G418抗性基因的真核細胞可以於含有G418的[[培養基]]中存活，而無這類基因的細胞則會在這種培養環境中死亡。研究人員可以利用這一點，於載體上加入''neo''基因。這樣，當把載體導入細胞時，''neo''基因也會一併導入。之後，在培養基中加入G418即可殺死未能成功導入載體的細胞，而留下成功導入載體的細胞，利於後續研究的進行<ref name=In/><ref name=Lodish2013>{{cite book|year=2013|title=Molecular Cell Biology (7th edition)|section=Chapter5: Molecular Genetic Techniques|publisher=Macmillan Higher Education|author=Harvey Lodish et al.|ISBN=978-1-4641-0981-2|pages=171-223}}</ref>。

==參見==
*[[滅瘟素]]（Blast）
*[[嘌呤黴素]]（Puromycin）
*[[新黴素]]

==參考==
{{reflist}}

[[Category:抗生素]]