translation mechinary

Defination of translation
Components of translational machinery
1)Transfer RNA
2)Aminoacyl tRNA synthetase
3)Ribosomes
4)Messenger RNA
PROKARYOTIC TRANSLATION
EUKARYOTIC TRANSLATION
NECESSITY OF TRANSLATION
CONCLUSION

1. By
KAUSHAL KUMAR SAHU
Assistant Professor (Ad Hoc)
Department of Biotechnology
Govt. Digvijay Autonomous P. G. College
Raj-Nandgaon ( C. G. )

2. Definationoftranslation
Componentsoftranslationalmachinery
1)TransferRNA
2)AminoacyltRNAsynthetase
3)Ribosomes
4)MessengerRNA
PROKARYOTIC TRANSLATION
EUKARYOTICTRANSLATION
NECESSITYOFTRANSLATION
CONCLUSION

3. TheprocessbywhichmessengerRNAis
translatedintoproteins.
or
Theprocessinwhichthegeneticinformation
presentsinanmRNAmoleculespecifiesthe
sequenceofaminoacidduringprotein
synthesis.

4. Itbasicallyincludesfollowingcomponents-
1)TransferRNA
2)AminoacyltRNAsynthetase
3)Ribosomes
4)MessengerRNA

5. AllcellscontainasetoftransferRNAs(tRNAs),
eachofwhichisasmallRNAmoleculelength
between70and90nucleotides
EachhavingatleastonetypeoftRNAassignedto
it.Beforeanaminoacidisattachedbyitscarboxyl
endtothe3'endofanappropriatetRNA
molecule.Linkingcovalentlytheaminoacidtoa
tRNAcontainingthecorrectanticodons

6. EachtRNAmoleculerecognizesaspecificcodon.
Transferribonucleicacid(tRNA)isprimarily
synthesizedfromtRNAgenethroughtranscription
byRNApolymerase.
SynthesisoftRNAisregulatedbypromoter
activityandspecificfactors(ppGppand/or
pppGppinprokaryotesandMaf1ineukaryotes)
dependingonthenutrientconditionofthecell.

7. PrimarytranscriptsoftRNAgenescontain50and
30extrasequences,whichareremovedbyasetof
responsiblenucleases.
InsomecasestRNAtranscriptscontainintrons,
whicharesplicedoutbyaspecificendonuclease
andtheresultanttwofragmentsarejoinedby
RNAligasess

9. theloopclosesttothe5'endiscalledthe
dihydrouridinearm(Darm),ascontains
dihydrouridinebases,(unusualnucleotides
commononlytotRNA).
Theloopclosesttothe3'endiscalledtheTarm,
afteritssequenceofthymine-pseudouridine-
cytosine(pseudouridineisalsoanunusualbase).

10. bottomloopofthecloverleafcontainsthe
anticodon,whichbindscomplementarilytothe
mRNAcodon.
Atthe3'endofthetRNAmolecule,extendsa
threenucleotideacceptorsiteincludingafree-OH
group.
sAspecifictRNAbindstoaspecificaminoacid
throughitsacceptorarms.

11. sometRNAmoleculescanbindtotwoorthree
differentcodons.3'endoftheanticodonismore
spatiallyconfinedthanthe5'endresultingthe5'endof
theanticodonfreetohydrogenbondwithseveralbase
groupslocatedatthe3'positionofthecodon.Thisidea
iscalledthewobblehypothesis.The5'positionis
calledthewobblepositionbecauseitcanmoveThe
wobblehypothesismeansthatifthefirstandsecond
positionsarethesame.

12. TheattachmentofaminoacidstospecifictRNAsis
mediatedbyagroupofenzymescalledaminoacyltRNA
synthetase(PaulZamecnik,andMahlonHoaglandin1957)
aminoacid+ATP→aminoacyl-AMP+Pp
i
aminoacyl-AMP+tRNA→aminoacyl-tRNA+AMP
Sumof1and2:aminoacid+tRNA+ATP→aminoacyl-
tRNA+AMP+PP
i

13. ClassI
hastwohighlyconservedsequencemotifs
usuallymonomericordimeric.
ClassII
hasthreehighlyconservedsequencemotifs
usuallydimericortetrameric

14. Bothclassesofaminoacyl-tRNAsynthetases
aremultidomainproteins.
AnaaRSconsistsofacatalyticdomain(where
boththeabovereactionstakeplace)
Ananticodonbindingdomain(which
interactsmostlywiththeanticodonregionof
thetRNAandensuresbindingofthecorrect
tRNAtotheaminoacid).

16. FirstobservedbyRomaniancellbiologist
GeorgePalade(1950)Theterm"ribosome"was
proposedbyscientistRichardB.Robertsin
1958
Ribosomesarethesitesofproteinsynthesisin
bothprokaryoticandeukaryoticcells.
RibosomesaremadefromcomplexesofRNAs
andproteinscalledribonucleoproteins.

17. Inbacterialcells,ribosomesaresynthesizedinthe
cytoplasmthroughthetranscriptionofmultipleribosome
geneoperon.
FREERIBOSOMES-moveaboutanywhereinthecytosol,
butareexcludedfromthecellnucleusandotherorganelles.
MEMBERANE BOUND RIBOSOMESWhenaribosome
beginstosynthesizeproteinsthatareneededinsome
organelles,theribosomemakingthisproteincanbecome
"membrane-bound".-

18. Prokaryotes
70Sribosomes,
small(30S) large(50S)
subunit.
16SRNAsubunit 5SRNA,
23S
Eukaryotes
80Sribosomes,
small(40S) large(60S)
subunit.18S 5,5.8,28sRNA

20. TheribosomecontainsthreeRNAbinding
sites,designatedA,PandE.
TheAsitebindsanaminoacyl-tRNA(atRNA
boundtoanaminoacid)
thePsitebindsapeptidyl-tRNA(atRNA
boundtothepeptidebeingsynthesized)
andtheEsitebindsafreetRNAbeforeitexits
theribosome.
s

22. Blueprintofproteinreproduction.
TranscribedfromDNA
mRNAtransfersgeneticinformationfromthe
cellnucleusintotheprotein-producing
ribosomeslocatedinthecytoplasm.
Eachcodoncorrespondstoaspecificamino
acid,andthesequenceofcodonsendswitha
codonthathasastopsignal.

23. Itisanimmaturesinglestrandofmessenger
ribonucleicacid(mRNA).
synthesizedfromaDNAtemplateinthecell
nucleusbytranscription.
comprisesthebulkofheterogeneousnuclear
RNA(hnRNA).
ThetermhnRNAisoftenusedasasynonym
forpre-mRNA..

24. Initiationoftranslationinprokaryotesinvolvesthe
assemblyofthecomponentsofthetranslation
systemwhichare:
thetworibosomalsubunits(50S&30Ssubunits)
themRNAtobetranslated,thefirst(formyl)
aminoacyltRNA(thetRNAchargedwiththefirst
aminoacid),
GTP(asasourceofenergy),
threeinitiationfactors(IF1,IF2,andIF3)which
helptheassemblyoftheinitiationcomplex.

26. startswhenthefmet-tRNAentersthePsite,causinga
conformationalchangeopeningtheAsiteforthenew
aminoacyl-tRNAtobind.
bindingisfacilitatedbyelongationfactor-Tu(EF-Tu),
asmallGTPase
ThegrowingpolypeptideconnectedtothetRNAin
thePsiteisdetachedfromthetRNAinthePsiteanda
peptidebondisformedbetweenthelastaminoacidsof
thepolypeptideandtheaminoacidstillattachedtothe
tRNAintheAsite.

27. Thisprocess,knownaspeptidebondformation,is
catalyzedbyaribozyme
TheAsitehasthenewlyformedpeptide,whilethe
PsitehasanunchargedtRNA(tRNAwithno
aminoacids).ThenewlyformedpeptideintheA
sitetRNAisknownasdipeptideandthewhole
assemblyiscalleddipeptidyl-tRNA.

29. Terminationoccurswhenoneofthethreetermination
codonsmovesintotheAsite,recognizedbyproteins
calledreleasefactorsnamelyRF1(recognizingthe
UAAandUAGstopcodons)orRF2(recognizingthe
UAAandUGAstopcodons).
Thesefactorstriggerthehydrolysisoftheesterbondin
peptidyl-tRNAandthereleaseofthenewly
synthesizedproteinfromtheribosome.
AthirdreleasefactorRF-3catalyzesthereleaseofRF-1
andRF-2attheendoftheinitiation

31. TheinitiationfactorseIF4EandeIF4G,inassociation
witheIF4AandeIF4B,thenbringthemRNAtothe40S
ribosomalsubunit,witheIF4GinteractingwitheIF3.
The40Sribosomalsubunit,inassociationwiththe
boundmethionyltRNAandelFs,thenscansthe
mRNAtoidentifytheAUGinitiationcodon.
WhentheAUGcodonisreached,eIF5triggersthe
hydrolysisofGTPboundtoeIF2.Initiationfactors
(includingeIF2boundtoGDP)arethenreleased,
anda60Ssubunitbindstothe40Ssub-unittoformthe
80Sinitiationcomplexofeukaryoticcells.

33. Duringchainelongation,eachadditional
aminoacidisaddedtothenascentpolypeptide
chaininathree-stepmicrocycle
positioningthecorrectaminoacyl-tRNAinthe
Asiteoftheribosome
formingthepeptidebond
shiftingthemRNAbyonecodonrelativeto
theribosome.

35. theribosomeengagesinaprocesscalled
translocation:
spurredbyelongationfactors,theribosome
movesthreenucleotidesinthe3'primedirection
alongthemRNA.
Inotherwords,theribosomemovessothatanew
mRNAcodonisaccessibleintheAsite.

38. Terminationofelongationisdependenton
eukaryoticreleasefactor.
Aterminationcodon(e.g.,UAA)attheAsite
isrecognizedbyareleasefactorratherthanby
atRNA.
Theresultisthereleaseofthecompleted
polypeptidechain,followedbythedissociation
oftRNAandmRNAfromtheribosome.

40. Itisthemostessentialprocessforthe
conversionofmRNAtoproteinwithoutwhich
nogenewouldbeabletocodeanyfunctional
protein,whichformsthebasisofmanycellular
andmetabolicprocesses.

41. Thetranslationalmachineryistheconserved
part,aidsintheconversionofthelanguageof
mRNAtothelanguageoffunctionalprotein.
Thisisthemostessentialeventfortheproper
codingbygenesforthevariousmetabolicand
cellularaspectsofbody.

42. The cell: A molecular approach by Cooper –
Hausmann
Cell and Molecular Biology by Gerald Karp
Internet source
www.translationwiki.com
www.translationsparknotes.com