Page 354 - Color Atlas of Biochemistry

Connective tissue 345

A. Structure of collagens B. Biosynthesis

Special amino acids: Gene
4-Hydroxyproline (4Hyp)
3-Hydroxyproline (3Hyp) Transcription
5-Hydroxylysine (5Hyl)

– Gly – X – Y – Gly – X – Y – Gly – X – Y –
Basic unit Translation
Primary structure
Pre-procollagen
O C OH
1
Hyl C CH 2 CH 2 C CH 2 NH 3 2 1 2

HN H 3
C O 4 Intracellular
H 2
HO C Hyp = Y 5 protein
CH modification
C
N
H C
H 2 Exocytosis
C O
H 2
C Pro = X
CH
C
H 2
N
C Procollagen
H 2
C O
Gly 6
H 2 C
7
NH
8 3
Extracellular
9 protein
modification

Type I tropocollagen 285 kDa
~
Collagen fibril

1 Removal of the prepeptide
Overlap Gap Diameter 2 Hydroxylation of Pro and Lys residues
D = 64 - 67 nm 40 nm 1.5 nm
3 Glycosylation of 5Hyl and Asn

4 Oxidation of Cys in propeptides
5 Assemblage to form triple helix
6 Removal of the propeptide

Length 400 nm 7 Staggered deposition to form fibrils
8 Oxidation of Lys and 5Hyl to aldehydes
9 Cross-linking to form supramolecules

20-500 nm 1 Procollagen-proline 4-dioxygenase 1.14.11.2
[ascorbate, Fe]
Procollagen-lysine 5-dioxygenase 1.14.11.4

Collagen fibril (section) 2 [ascorbate, Fe]
3
Protein-lysine 6-oxidase 1.4.3.13 [Cu]

Koolman, Color Atlas of Biochemistry, 2nd edition © 2005 Thieme
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