Structure and Function of Nucleic Acid

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? ? ?????????

• Structure and Function of Nucleic Acid

The biochemistry and molecular biology department
of CMU
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? ?(nucleic acid)
??????????????????,??????????
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????????
????????????
??????,???????????(genotype)?
?????????????
?????????????????RNA????????????
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??? ???????????? The Chemical Component and
Primary Structure of Nucleic Acid
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????????????? (nucleotide)?
??
??
??
???
??
??
DNA??????????????? ? RNA????????????? ?
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????????
???(A)
??
DNA?RNA??
???(G)
??
???(C)
DNA?
??
????(T)
RNA?
???(U)
??????????? ?
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? ?
??(purine)
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??(pyrimidine)
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• ??????????-??????-???????????????????????????????

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? ?
??(ribose)
????(deoxyribose)
(??DNA)
(??RNA)
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?????(?????)???????????(nucleoside) (?????)?
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??(????)?????????????(?????)?
??? AMP, GMP, UMP, CMP ????? dAMP, dGMP, dTMP,
dCMP
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• ??????
• NMP,NDP,NTP

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• ????? cAMP,cGMP

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?????????

• ??
• ????????????
• ????????????????,??????????

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C
??????3 ?, 5 ? -??????????????,????
A
G
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????
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• DNA ?RNA???

?? ?? ??
DNA A?G?C?T ????
RNA A?G?C?U ??
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??? DNA????????Dimensional Structure and
Function of DNA
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?? DNA????? ?????
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(?)DNA??????????

• ??????
• Chargaff ??A T
• G C

• ?????????
• A-T?G-C????????

• DNA???X-???????

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• ?????????

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(?) DNA?????????
1. ???????,?????????????? (double
helix)?????2nm,????????? 2. ??-????????????,??????
?????????????10???? (bp),???3.4nm?
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?????????,?????????
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3. ?????????????,A?T?????,C?G?????,??A-T?C-G?????,
????????? 4. ???????????????,???????????
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??????
G
C
T
A
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(?)DNA?????????
Z?DNA
A?DNA
B?DNA
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??DNA????????????????
(?)DNA??????
?????(superhelix ?supercoil) DNA????????????????
????(positive supercoil) ?????DNA???????
????(negative supercoil) ?????DNA???????
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?? DNA??????????????????????DNA???RNA???????????
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(?)????DNA?????
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(?)DNA????????????
????????DNA??????,?????? ???(nucleosome)?
?????? DNA?200bp ???H1 H2A,H2B H3 H4
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????????
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DNA?????
??????
?????
????????
????????
?????
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???????DNA??
???
???
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??DNA???
DNA??????????????????,?????????????????????????,??
????????????
????????,??DNA????????,???????????????????
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?????????? Oswald Avery (1944)
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• ???,????????

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??? RNA??????
Structure and Function of RNA
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???????RNA??????
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? ???RNA??????
mRNA????
??? (intron)
??? (exon)
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mRNA????
1. ?????mRNA?5???????????7-????,?????????C2?????
,??????m7GpppNm-?
2. ?????mRNA?3?????????? (polyA)??,????A??
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????
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???????A????
mRNA???????? mRNA?????? ???????
mRNA??????????????
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????RNA??????

• tRNA???????
• ???????
• 3??? CCA-OH
• 5??????G
• ?7090??????

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????
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tRNA????? ????
????
???
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• tRNA?????
• ?L?

• tRNA???
• ????????????,?????????

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??????RNA??????
rRNA???
rRNA??? ????????,?????????????
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??????
???? ????
??? 30S 40S
rRNA 16S 18S
??? 21? 33?
??? 50S 60S
rRNA 23S 5S 28S 5.8S 5S
??? 33? 49?
??? 70S 80S
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? ??????RNA?RNA??
snmRNAs
??????RNA?,????????????????????RNA,????mRNA?RNA
(small non-messenger RNAs,snmRNAs)?
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snmRNAs??? ???RNA (snRNA) ???RNA (snoRNA) ???RNA
(scRNA) ????RNA ????? RNA (siRNA)
snmRNAs??? ??hnRNA?rRNA??????????????????????
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RNA?? (RNomics)
??????snmRNAs?????????????????????????????????????
?????snmRNAs??????????????
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? ? ?
??????? The Physical and Chemical Characters of
Nucleic Acid
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???????????

• ??????,???????
• DNA??????,????
• ?260nm????????,???????????????????????????????

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(No Transcript)
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OD260???
1. DNA?RNA??? OD2601.0??? 50 ?g/ml??DNA 40
?g/ml??DNA(?RNA) 20 ?g/ml???? 2.????????? DNA??
OD260/OD280 1.8 RNA?? OD260/OD280 2.0
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??DNA???(denaturation)
????????????,DNA?????????????
???????,?,????
????????????
OD260?? ????
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DNA??????????????
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• ????DNA??????OD260??????

DNA???????
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• ?????????DNA????????A260???,????????????

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• Tm????????????50??????DNA?????,??????(melting
  temperature, Tm)?????GC??????

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??DNA????????
DNA??(renaturation)??? ??????,??DNA???????????????
??,?????????
????DNA??????????,????????(annealing) ?
???? DNA???,???OD260???
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?????? (hybridization)

• ????DNA??????,??????????????DNA???DNA?RNA????????
  ????

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??
??
??
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????????? ??DNA??????????? ?????????????? ????????
?????????? ??????????
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??? ? ? ? Nuclease
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• ???????????????
• ????????
• DNA?(deoxyribonuclease, DNase)
• RNA? (ribonuclease, RNase)
• ??????????
• ?????
• ????????
• ?????????
• ?????
• 5?3?3?5??????

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??????
?????????????????????

• ??DNA???????RNA????????????????????
• ??????????????????,?????????????????
• ?????????????????
• ????DNA?????????

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? ?

• ???RNA (ribozyme)
• ???????????
• ??RNA???????
• ????????????????mRNA?

• ???DNA (DNAzyme) ??????????????,?????????RNA?