7/30/2019 Collagen Structure and Synthesis IUA 2013

1/22

Collagenstructureandsynthesis

Dr. Atif Hassan Khirelsied

DepartmentofBiochemistryFacultyofMedicine

InternationalUniversityofAfrica

7/30/2019 Collagen Structure and Synthesis IUA 2013

2/22

Colla enisinsolublefibrous rotein.

Mainlyfoundintheextracellularmatrixandinconnective

.

Themostabundantproteininmammals(>25%ofbody

.

Hasgreattensile strength,inligaments andtendons.

7/30/2019 Collagen Structure and Synthesis IUA 2013

3/22

Isresponsibleforskinelasticity,anditsdegradationleads

towrinkles thataccom an a i n .

Fillsoutthecornea whereitispresentincrystallineform.

Also

used

in

cosmetic surgery,

e.g.,

lip

enhancement.

7/30/2019 Collagen Structure and Synthesis IUA 2013

4/22

,

thecollageninthebodyconsistsoftypesI,II,andIII

Themostabundanttypesofcollagen

7/30/2019 Collagen Structure and Synthesis IUA 2013

5/22

Type RepresentativeTissues

Fibrillar collagens

I Skin,

tendon,

bone,

ligaments,

dentin,

interstitial

II Cartilage,vitreoushumor

III Skin,muscle,bloodvessels

V SimilartotypeI;alsocellcultures,fetaltissues

VI Mostinterstitialtissues

,

IV Allbasallaminaes

7/30/2019 Collagen Structure and Synthesis IUA 2013

6/22

Insolubleglycoprotein (protein+carbohydrate)

Protein

Highglycine andtwomodifiedaminoacidshydroxylysine,

hydroxyproline (glyXY)n.

Carbohydrate (glucose,galactose)

7/30/2019 Collagen Structure and Synthesis IUA 2013

7/22

CollagenstructureCollagenstructure

Collagenisa

fibrous roteinbuilt

upof three

chains(not helices)

whichformaro e

like triplehelix.

7/30/2019 Collagen Structure and Synthesis IUA 2013

8/22

Collagenhasanunusual

am noac compos on,

every chainconsistsofa

repeatingtriplet(GlyXY).

7/30/2019 Collagen Structure and Synthesis IUA 2013

9/22

T eg yc ne issma enoug to itintot ecentero t e

triplehelix.

Inadditiontotheglycine collagencontains(proline,

h drox roline and h drox l sine .

Theselateraminoacidsresultsfromposttranslational

.

7/30/2019 Collagen Structure and Synthesis IUA 2013

10/22

Proline isfoundintheXpositionand4hydroxyproline in

theYposition.

Thehydrogenbonding stabilizesthetriplehelix.

7/30/2019 Collagen Structure and Synthesis IUA 2013

11/22

Interchain hydrogenbondingincollagen.The amidehydrogenof

oxygenofaresidue,oftenproline,inanadjacentchain.

7/30/2019 Collagen Structure and Synthesis IUA 2013

12/22

CollagenstructureCollagenstructure

Covalentcrosslinksincollagen.(a)Anallysine residuecondenseswith

alysineresiduetoformanintermolecularSchiffbasecrosslink.(b)Two

allysine residuescondensetoformanintramolecular aldol crosslink.

7/30/2019 Collagen Structure and Synthesis IUA 2013

13/22

TypeIcollagenisthemostcommonfibrillarcollagen (90%),

andisfoundinbone,skin,tendons,vascular,ligature,organs,.

TypeIIcollagenprovidessimilartensilestrengthtocartilage.

o agen ype ret cu ar ersw t type .

TypeIVandVIIcollagensarenetworkformingcollagens;they

ormames wor ,part cu ar y n asa am na.

7/30/2019 Collagen Structure and Synthesis IUA 2013

14/22

CollagensynthesisCollagensynthesis

7/30/2019 Collagen Structure and Synthesis IUA 2013

15/22

CollagenDiseases Excess

1. Fibrosis.

. ung pu monary ros s.

3. Liver overconsumptionofalcohol.

4. Arteries atherosclerosis.

7/30/2019 Collagen Structure and Synthesis IUA 2013

16/22

CollagenDiseases Insufficient

. u vy

2. EhlersDanlos syndrome (rubberman)

3. Osteogenesis imperfecta

4. Atopic ermatitis AD

7/30/2019 Collagen Structure and Synthesis IUA 2013

17/22

.

2. Neededforhydroxylationofprolineandlysine.

3. Formtoofewhydrogenbondsincollagen.

4. Skin,bone,teethweaknessandmalformation.

. , .

7/30/2019 Collagen Structure and Synthesis IUA 2013

18/22

1. Malaise

and

lethargy

and

bone

pain2. Skinchangeswithroughness,easy

ru s ng

an

petec ae.

3. Gumdisease loosenin ofteeth

4. Poorwoundhealing,andemotional

changes.

7/30/2019 Collagen Structure and Synthesis IUA 2013

19/22

7/30/2019 Collagen Structure and Synthesis IUA 2013

20/22

Skinandtendonseasilystretched

Characterizedb ;

1. loosejoints.

2. Elasticskin,""Indiarubber

s n

7/30/2019 Collagen Structure and Synthesis IUA 2013

21/22

1. Brittlebonesyndrome

.

3. Failtoassembletriplehelix

4. Degradeimperfectcollagen

5. Leadstofragilebones

7/30/2019 Collagen Structure and Synthesis IUA 2013

22/22

,

or"Lobstein syndrome

Is

c aracterize

y

a norma

one

formationinbabies