Page 1 of 1: collagen basic structure

tanmay_mehta · Credits: 17113 My Scrapbook My Reading List 3 Books

Collagen is a major fibous protine of extracellular connective tissues, and it is also the most ubiquitous and pletiful In the animal Kingdom. Some 25-35% of body protine is collagen.

Collagen fibers gives strengh and structure to tissue in the body. Fibroblast cell produce collagen which from tissue structure and they contain collagen fibers arranged in three dimentions. Fibrils are smaller units of collagen fibers which are made of a repeating pattern of collagen molecules. The gaps and overlapping region between the molecules are specific, the gaps are there where the molecules may be cross linked.

The collagen molecule is a rigid rod 2900A0 by 15A0 ,triple helical structure. The major portion consists of three amnioacid chains, each in a left handed delical conformation to make on super helix molecule with frayed non helical ends.

Charaterised by repetitive Gly-X-Y sequences where glycine is In every third residue, and stabilized by proline and hydroxyproline resiues. Glycine has the hydrogen atom, the only element small enough to fit in the center of the super helix.

There are various 13 types of collagen Identified so far by scientists and they are characterized collagen are type 1 and type 3.

Collagen present in the body gives strength and structure to the tissues.In hard tissues inckuding bone, collagen functions to provide supports. In soft tissues, collgen matrix gives from and Integrity to tissues, In cardiovascular tissues, collagen froms a stiff layer that allow the artery a maximum exansion beyond which the artery would burst, thus providing protection.

parin · Credits: 14640 My Scrapbook My Reading List 1 Books

collagen triple helix has 3.3 residues per turn..

In repetitive Gly-X-Y pattern, Y is generally proline or hydroxyproline..

Scurvy:

It is a disorder d/t vit C deficiency.

Biochemical basis: collagen is initially synthesized as procollagen in which prolyl & lysys residues are hydroxylated by prolyl hydroxylase & lysyl hydroxylase respectively, these enzymes require ascorbic acid(vit C). hydroxyprolyl & hydroxylysys residues provide additional hydrogen bonding capability that stabilizes the mature protein.

So in scurvy, deficit in no of hydroxyproline & hydroxylysine residues undermines conformational stability of collagen fibres leading to bleeding gums, poor wound healing & swelling of joints..

Menke's syndrome:

d/t dietary deficiency of copper c/b kinky hair & growth retardation.

Biochemical basis: from precursor of collagen, certain lysyl residues are modified by lysyl oxidase, a copper containing protein that converts E-amino groups to aldehydes. Lysyl oxidase catalyzes a key step in formation of cross-links that strengthen colagen fibres..

Osteogenesis imperfecta:

It is a disorder c/b osteopenia, brittle bones, blue sclerae, dental abnormalities, progressive hearing loss.. there are 4 types in classification by Sillence..

Biochemical basis: most have mutations in one of the two genes that encode type I collagen.

Ehlers-Danlos syndrome:

a conective tissue disorder.

Biochemical basis: There are defects in genes that encode alpha collagen 1, procollagen N-peptidase or lysyl hydroxylase. which results in mobile joints & skin abnormalities.

reverend · Credits: 150 My Scrapbook

Thank you! I saw this question in the question paper for the 1st proff MBBS.

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