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2003-02-15 11:51:58 | Hit : 10952 | Vote : 2315 |
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Çö󽺹̵å DNAÀÇ Áغñ |
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Preparation of plasmid DNA (Çö󽺹̵å DNAÀÇ Áغñ)
Çö󽺹̵å´Â ÇÁ·£½ºÆ÷¸ÞÀ̼ÇÀ» À§ÇÑ º¤Åͷμ ¾²ÀÔ´Ï´Ù.
Áö±ÝÀº °ÅÀÇ ¸ðµç º¤Å͸¦ »ç¼ ¾²°í ÀÖÁö¸¸, ÀÌ ÇÃ¶ó½º¹Ìµå º¤Å͸¦ ¾î¶»°Ô ±¸ÇÏ´ÂÁö ¾Ë¾Æº¾½Ã´Ù.
(1) Å©±â¿¡ ±âÃÊÇÑ Çö󽺹̵å DNAÀÇ ºÐ¸®(Separation on the basis of size)
¨ç EDTA¿Í ¶óÀ̼ÒÀÚÀÓ(lysozyme)À» ¼öÅ©·Î½º(sucrose) Á¸ÀçÇÏ¿¡ ó¸®ÇÏ¸é ¼¼Æ÷(cell)ÀÇ ±ÞÁøÀû »êÈ(immediately bursting)¸¦ ¸·À¸¸é¼,
ºÎºÐÀûÀ¸·Î Æı«(degrade)µÈ ¼¼Æ÷º®(cell wall)°ú ¼Ò·®ÀÇ ¼¼Æ÷¸·(intact cytoplasmic membrane)ÀÌ ³²¾ÆÀÖ´Â »óÅÂÀÎ sphaeroplast°¡ Çü¼ºÀÌ µË´Ï´Ù.
ÀÌ ¶§´Â ¾ÆÁÖ ¹Ì·®ÀÇ ¿°»öÁú DNA(chromosomal DNA) Æı«¸¸ ÀϾ´Ï´Ù.
¨è Triton X-100°°Àº ¹«À̿¼º ¼¼Á¦(non-ionic detergent)¸¦ Ãß°¡ÇÏ¸é ¼¼Æ÷¿ëÇØ(cell lysis)°¡ µË´Ï´Ù.
±×·¯³ª SDS(sodium dodecyl sulfate)¸¦ »ç¿ëÇϸé, ¿°»öÁú ºÐÇØ(chromosomal breakage)¸¦ ¾ß±âÇÏ°Ô µÇ¹Ç·Î Àß »ç¿ë¾ÈÇÕ´Ï´Ù.
¨é ±×·± ÈÄ¿¡ ¿ø½ÉºÐ¸®(centrifugation)¸¦ Çϸé Çö󽺹̵å DNA(plasmid DNA)·Î ÀÌ·ïÁø ¸¼°Ô ¿ëÇØµÈ »óÃþ¾× ¹°Áú(cleared lysate)ÀÌ ³ª¿É´Ï´Ù.
Áï, DNA Á¶°¢(DNA fragment)°ú ¼¼Æ÷Â±â(cell debris)´Â ¾Æ·¡¿¡ ½×ÀÌ°Ô µÇÁö¿ä.
* ´ÜÁ¡ : ±×·¯³ª ¸¼°Ô ¿ëÇØµÈ »óÃþ¾× ¹°Áú(cleared lysate)¿¡ ¾à°£ÀÇ ¿°»öÁú DNA(chromosomal DNA)°¡ ³²À» ¼öµµ ÀÖ½À´Ï´Ù.
¶ÇÇÑ Çö󽺹̵å DNA(plasmid DNA)°¡ Å©±â°¡ Ŭ °æ¿ì ¼¼Æ÷Â±â(cell debris)¿Í ħÀü °¡´É¼ºÀÌ ÀÖ´Â ´ÜÁ¡ÀÌ ÀÖ½À´Ï´Ù.
(2) ±¸Á¶¿¡ ±âÃÊÇÑ Çö󽺹̵å DNAÀÇ ºÐ¸®(Separation on the basis of conformation)
# Çö󽺹̵å(plasmid)ÀÇ ±¸Á¶(conformation)¿¡ ´ëÇؼ ¸ÕÀú ¾Ë¾Æº¾½Ã´Ù.
¿øÇüÀÌÁß°¡´Ú DNA(double stranded DNA circle)ÀÌ ²Ï ´Ù¸¥ µÎ°¡Áö ±¸Á¶(conformation)¸¦ °¡Áö¹Ç·Î Çö󽺹̵å(plasmid)°¡ ¿øÇü±¸Á¶(circular form)ÀÌ¶ó ¸»Çϱ⠾î·Æ½À´Ï´Ù.
* Ãʳª¼±Çü ¸ð¾ç(supercoiled form)
¸¹Àº plasmid°¡ ÀÌ »óÅ·ΠÁ¸ÀçÇÏ´Ù°¡ ÇÃ¶ó½º¹Ìµå º¹Á¦(plasmid replication) µ¿¾È¿¡´Â ÅäÆ÷¾ÆÀ̼Ҹӷ¹ÀÌÁî(topoisomerase) ºÒ¸®´Â È¿¼Ò(enzyme)¿¡ ÀÇÇØ ºÎºÐÀûÀ¸·Î °¨±âÁö ¾ÊÀº Çö󽺹̵å DNA(unwound plasmid DNA)°¡ À̶§ »ý±é´Ï´Ù.
Ãʳª¼±Çü ±¸Á¶(supercoiled conformation)´Â Æú¸®´ºÅ¬·¹¿ÀŸÀ̵å (polynucleotide)°¡ ¿ÏÀüÇÒ¶§, Áï °øÀ¯°áÇÕÀûÀ¸·Î ´ÝÈù ¿øÇü DNA(covalently closed-circular(ccc) DNA)À϶§¸¸ À¯Áö°¡ µË´Ï´Ù.
¸¸¾à, Æú¸®´ºÅ¬·¹¿ÀŸÀÌµå °¡´Ú(polynucleotide strand)ÀÇ Çϳª°¡ ±úÁö¸é ÀÌÁß³ª¼±±¸Á¶(double helix)°¡ º¸Åë ÀÌ¿ÏµÈ »óÅÂ(normal relaxed state)ÀÎ, ¿¸° ¿øÇü DNA ±¸Á¶(open circular(OC) form)·Î ¹Ù²ò´Ï´Ù.
¡Å Ãʳª¼±Çü(supercoiling)ÀÇ ±¸Á¶(conformation)¸¦ ÀÌ¿ëÇÏ¿© non-supercoiled molecule¿¡¼ supercoiled moleculeÀ» ½±°Ô ºÐ¸®°¡ °¡´ÉÇÏ°Ô µË´Ï´Ù.
¨ç Alkaline denaturation (¾ËÄ«¶óÀÎ º¯¼º)
* Á¼Àº pH ¹üÀ§¿¡¼ non-supercoiled DNA´Â denatureµÈ´Ù.
* ¹Ý¸é, supercoiled DNA´Â denature°¡ µÇÁö ¾Ê´Â´Ù.
¨Í sodium hydrooxide(NaOH)¸¦ cell extract³ª cleared lysate¿¡ ÷°¡ÇÑ´Ù.
¨Î pH°¡ 12.0 ~ 12.5 »çÀÌ·Î º¯ÇØ non-supercoiled DNA moleculeÀÇ hydrogen bonding(¼ö¼Ò°áÇÕ)ÀÌ ±úÁø´Ù.
¨Ï acid°¡ ÷°¡µÇ¸é, bacterial denatured DNA reaggregate(Àç¸ðÀÓ) µÇ¾î tangled mass(¾ûŲ µ¢¾î¸®)¸¦ Çü¼ºÇÑ´Ù.
¨Ð centrifugeÇؼ supernatant(»ó¾×Ãþ)ÀÇ pure plasmid DNA¸¦ ¾ò´Â´Ù.
ÀåÁ¡ : SDS¿¡ ÀÇÇÑ cell lysis¿Í sodium acetate¿¡ ÀÇÇÑ neutralization(ÁßÈ) »óȲ¿¡¼ protein°ú RNA´Â insolubleÇÏ¿© centrifugation(¿ø½ÉºÐ¸®) step¿¡¼ Á¦°ÅµÈ´Ù.
¡æ phenol extraction°ú ribonuclease treatment(RNA Á¦°ÅÁ¦ °øÁ¤)°¡ ÇÊ¿ä¾ø´Ù.
¨è Ethidium bromide-caesium chloride density gradient centrifugation (Ethidium bromide-CsCl)
equilibrium(ÆòÇü)À̳ª density gradient centrifugation ±â¹ýÀ» ÀÀ¿ëÇÑ ¹æ¹ýÀÌ´Ù.
caesium chloride(CsCl)À» ¸Å¿ì ³ôÀº ¼Óµµ·Î centrifugationÇϸé density gradient(¹Ðµµ ±×·¹µð¾ðÆ®)°¡ »ý±ä´Ù.
¡æ ³ôÀº centrifugal force(¿ø½ÉºÐ¸®·Â)°¡ caesuim(¼¼½·)°ú chloride ionÀ» tubeÀÇ ¹Ù´Ú¿¡ ´ç°Ü¼ gradient°¡ »ý±ä´Ù.
(downward migration(¾Æ·¡ÂÊÀ¸·Î À̵¿)ÀÌ diffusion(È®»ê)¿¡ ÀÇÇØ counterbalancedµÇ°í, CsCl density°¡ tube ¹Ù´Ú ÂÊÀ¸·Î ´õ Ä¿Á® concentration gradient°¡ »ý±ä´Ù.)
particular moleculeÀÇ band´Â ±×°ÍÀÇ buoyant density(ºÎ·Â ¹Ðµµ)¿¡ µû¶ó ƯÁ¤À§Ä¡ÀÇ gradient¿¡ band°¡ Çü¼ºµÈ´Ù.
* DNA buoyant density(ºÎ·Â¹Ðµµ) 1.7g/cm^3 ¡æ CsCl density gradient(ºÎ·Â¹Ðµµ)ÀÇ 1.7g/cm^3ÀÇ À§Ä¡¿¡ band°¡ À§Ä¡ÇÏ°Ô µÊ
* protein molecule : lower buoyant density(ºÎ·Â¹Ðµµ) ¡æ tube À§¿¡ ¶ä
* RNA : ¹Ù´Ú¿¡ pellet Çü¼º
¡Å DNA purification¿¡¼ÀÇ phenol extraction°ú ribonuclease treatmentÀÇ ´ëü¹ýÀÌ´Ù.
# EtBr (ethidium bromide)
double helix DNA¿¡¼ ÀÌ¿ôÇÑ base pair »çÀÌ¿¡ intercalating(»óÈ£°áÇÕÇÏ¿© ³¢¾îµë)ÇÏ¿© DNA molecule¿¡ bindingÇÑ´Ù.
¡æ double helixÀÇ ºÎºÐÀûÀÎ unwinding(Ç®¸²)À» À¯µµÇÑ´Ù. buoyant density(ºÎ·Â¹Ðµµ)¸¦ ÁÙÀÌ°Ô µÇ¾î linear DNAº¸´Ù 0.123g/cm^3À¸·Î ³·ÃçÁø´Ù.
±×·¯³ª, »ó´ëÀûÀ¸·Î supercoiled DNA´Â free end°¡ ¾ø±â ¶§¹®¿¡ °ÅÀÇ Ç®¾îÁöÁö ¾Ê¾Æ ¾ÆÁÖ Á¦ÇÑµÈ ¾çÀÇ EtBr¸¸ÀÌ binding(°áÇÕ)ÇÏ°Ô µÇ¹Ç·Î supercoiled moleculeÀÇ buoyant density(ºÎ·Â¹Ðµµ)´Â ¾ÆÁÖ ÀÛÀº ¾ç 0.085g/cm^3 ¸¸Å¸¸ ÁÙ¾îµé°Ô µÈ´Ù.
¡Å EtBr-CsCl gradient¿¡¼ supercolide moleculeÀº linear¿Í open-circular DNA¿Í ´Ù¸¥ position(À§Ä¡)¿¡ band¸¦ Çü¼ºÇÏ°Ô µÈ´Ù.
Ethidium bromide-caesium chloride density gradient centrifugationÀº pure plasmid DNA¸¦ ¾ò´Âµ¥ ¸Å¿ì È¿°úÀûÀÎ ¹æ¹ýÀÌ´Ù.
¡æ DNA bandÀÇ positionÀº tube¿¡ ultraviolet radiation(¹æ»ç¼±)À» ºñÃ߸é boundµÈ EtBrÀÌ Çü±¤À» ¶ì¾î ½Äº°ÇÒ ¼ö ÀÖ´Ù.(UV ¡æ red)
plasmid¿¡ bound(°áÇÕ)µÈ EtBrÀº n-butanol·Î ºüÁ®³ª¿À°Ô ÇÒ ¼ö ÀÖÀ¸¸ç, CsClÀº dialysis(Åõ¼®)·Î Á¦°ÅÇÑ´Ù.
¡æ 100 % pure plasmid preparation Áغñ°¡ °¡´ÉÇÏ°Ô µÈ´Ù ¡æ cloning vector·Î »ç¿ëÇÑ´Ù.
(3) Plasmid amplification (Çö󽺹̵å ÁõÆø)
plasmidÀÇ yield(¼öÀ²)¸¦ ³ôÀÌ´Â °Í
* multy copy plasmid : bacteria ¾È¿¡ 20°³ ÀÌ»óÀÇ plasmid copy number¸¦ °¡Áö°í ÀÖ´Ù.
bacterial chromosome(¿°»öü)Àº ¾Æ·¡ÀÇ condition(»óȲ)¿¡¼´Â replicate(º¹Á¦)ÇÏÁö ¸øÇÏ°í, protein synthesis(ÇÕ¼º) ¾øÀÌ plasmid DNA¸¸ replicate(ÇÕ¼º)ÇÒ ¼ö ÀÖ´Â ¼ºÁúÀÌ ÀÖ´Ù.
- plasmid DNA purification(Çö󽺹̵å DNA Á¤Á¦)À» À§ÇØ bacterial culture growth¿¡¼ cell density(¼¼Æ÷¹Ðµµ)°¡ ÃæºÐÇÏ°Ô µµ´ÞÇßÀ»¶§, protein synthesis inhibitor(´Ü¹éÁú ÇÕ¼º ¾ïÁ¦Á¦)ÀÎ chloramphenicolÀ» ÷°¡ÇÏ¿© 12½Ã°£ µ¿¾È culture¸¦ ´õ incubate(¹è¾ç)ÇÑ´Ù. À̶§ plasmid moleculeÀº °è¼Ó replicate(º¹Á¦)µÇ°í, chromosome replication(¿°»öü º¹Á¦)°ú cell division(¼¼Æ÷ ºÐ¿)Àº block(¸·À½)µÈ´Ù.
¡Å plasmid copy number°¡ ¾öû Áõ°¡ÇÏ¿© multy copy plasmidÀÇ yield(¼öÀ²)µµ Áõ°¡ÇÏ°Ô µÈ´Ù.
* ¿À¿µ¹Î´Ô¿¡ ÀÇÇؼ °Ô½Ã¹° À̵¿µÇ¾ú½À´Ï´Ù (2004-05-08 18:09)
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