mutasi gen mutasi gen mutasi gen mutasi gen

mutasi gen mutasi gen mutasi gen mutasi gen

1. MUTASI GEN
(PROKARIOT)
Sri Agung Fitri Kusuma

2. DEFINISI
Wild type
mutan
Varian
Genotip
Mutagen
Mutasi
fENOTIP

3. PENGARUH MUTASI TERHADAP PENGARUH MUTASI TERHADAP
AKTIVITAS PROTEINAKTIVITAS PROTEIN

5. FENOTIPE PADA GENETIKA BAKTERI
AUXOTROPHIC MUTANTS

6. RESISTANT MUTANTS

7. Types of DNA ChangeTypes of DNA Change

The simplest mutations are base changes, where one The simplest mutations are base changes, where one
base is converted to another. These can be classified base is converted to another. These can be classified
as either: as either:
–--“transitions”, where one purine is changed to another --“transitions”, where one purine is changed to another
purine (A -> G, for example), or one pyrimidine is changed to purine (A -> G, for example), or one pyrimidine is changed to
another pyrimidine (T -> C, for example). another pyrimidine (T -> C, for example).
–““transversions”, where a purine is substituted for a transversions”, where a purine is substituted for a
pyrimidine, or a pyrimidine is substituted for a purine. For pyrimidine, or a pyrimidine is substituted for a purine. For
example, A -> C.example, A -> C.

Another simple type of mutation is the gain or loss f Another simple type of mutation is the gain or loss f
one or a few bases.one or a few bases.

Larger mutations include insertion of whole new Larger mutations include insertion of whole new
sequences, often due to movements of transposable sequences, often due to movements of transposable
elements in the DNA or to chromosome changes elements in the DNA or to chromosome changes
such as inversions or translocations.such as inversions or translocations.

Deletions of large segments of DNA also occurs.Deletions of large segments of DNA also occurs.

8. TIPE MUTASI
 Missense mutation
 Nonsense mutation
 Insertion
 Deletion
 Duplication
 Frameshift mutation
 Repeat expansion

9. Missense Mutation
This type of mutation is a change in one DNA base pair that results
in the substitution of one amino acid for another in the protein
made by a gene.

10. Nonsense Mutation
A nonsense mutation is also a change in one DNA base pair. Instead of
substituting one amino acid for another, however, the altered DNA
sequence prematurely signals the cell to stop building a protein. This
type of mutation results in a shortened protein that may function
improperly or not at all.

11. Insertion
An insertion changes the number of DNA bases in a gene by
adding a piece of DNA. As a result, the protein made by the gene
may not function properly.

12. Deletion
A deletion changes the number of DNA bases by removing a piece of
DNA. Small deletions may remove one or a few base pairs within a
gene, while larger deletions can remove an entire gene or several
neighboring genes. The deleted DNA may alter the function of the
resulting protein(s).

13. Duplication
A duplication consists of a piece of DNA that is abnormally copied
one or more times. This type of mutation may alter the function
of the resulting protein.

14. Frameshift Mutation
This type of mutation occurs when the addition or loss of DNA bases
changes a gene's reading frame. A reading frame consists of groups of 3
bases that each code for one amino acid. A frameshift mutation shifts the
grouping of these bases and changes the code for amino acids. The
resulting protein is usually nonfunctional. Insertions, deletions, and
duplications can all be frameshift mutations.

15. Repeat Expansion
Nucleotide repeats are short DNA sequences that are repeated a
number of times in a row. For example, a trinucleotide repeat is made
up of 3-base-pair sequences, and a tetranucleotide repeat is made up
of 4-base-pair sequences. A repeat expansion is a mutation that
increases the number of times that the short DNA sequence is
repeated. This type of mutation can cause the resulting protein to
function improperly

16. MUTAGEN &
DNA REPAIR

17. PENYEBAB MUTASI
Base analogs kesalahan replikasi oleh DNA
polimerase
Faktor lingkungan : panas, radiasi
Zat kimia : alkilasi, deaminasi, zat penginterkalasi,
oksigen reaktif

18. DNA REPAIR
 SPECIFIC REPAIR
 GENERAL REPAIR

19. SPECIFIC REPAIR

20. DEAMINASI BASA
Hilangnya gugus amino dari adenine, cytosine dan guanine
Spontan atau karena zat kimia tertentu (deaminating agent)
Deaminating agent :
 hydroxylamine : deaminasi cytosine (GC AT), in vitro
Bisulfite : deaminasi cytosine pada ssDNA, site directed
mutagenesis
Nitrous acid : deaminasi adenine, cytosine dan guanine
(GC AT, AT GC), in vitro dan in vivo
Repair Deaminasi basa :
DNA glikosilase
 AP endonuklease

21. Deaminasi basa oleh Nitrous acid

22. Repair Deaminasi Basa
DNA glikosilase
AP endonuklease

23. Deaminasi 5-methylcytosine
Mutasi menghasilkan timin
Pada E. coli biasanya terjadi pada 5’CCWGG3’/ 3’GGWCC5’
(W =AT atau TA)
GT mismatch
Repair : vsr endonuklease,
Vsr (endonuklease) berikatan dgn mismatch TG
Pemotongan setelah T pada urutan 5’CmCAGG3’/3’GGTTC5

24. OKSIGEN REAKTIF
Bentuk : radikal superoksida, hidrogen peroksida, radikal
hidroksil
Pada bakteri : superoksida dismutase, katalase, peroksida
reduktase
8-oxoG (GO) : mutagenic agent, oxdized 7,8_dihydro-8-
oxoguanine , MISPAIR DENGAN ADENINE
Repair untuk 8-oxoG (GO) : gen mut
mutM : DNA glycosylase (remove 8 –
oxo G)
AP endonuclease
mutY : DNA glycosylase (remove A)
mutT : mencegah 8-oxoG masuk ke
DNA

25. Sistem Repair Gen mut

26. ALKILASI
Penambahan gugus alkil (CH
3
, CH
3
CH
2
, etc)
Oleh zat kimia ethyl methanasulfonate (EMS), methyl
methanesulfonate (MMS), nitrosoguanidine
Repair :
 N-glikosilase spesifik, Ap endonuklease
Metiltransferase (repair alkilasi pada karbon 0
6
(guanin) dan
karbon 0
4
(timin) )
Adaptive respoonse

27. Adaptive Response

28. Dimer Pirimidin
 UV irradiation
 Repair :
Photoreactivation : pholyase
N-glikosilase

29. Tipe Dimer Pirimidin

30. Repair Dimer Pirimidin

31. GENERAL DNA REPAIR MECHANISMS
Methyl-directed mismatch repair (mutS, mutL dan mutH)
Nucleotide excision repair
Postreplication/ recombination repair (recA)
SOS inducible repair (lexA, recA, umuDC)

32. Methyl-directed Mismatch Repair

33. Nucleotide Excision Repair