15 Fibrous Protein Example: Explanation You Should Know


Fibrous proteins, also known as scleroproteins, belong to one of the three major proteins (along with globular and membrane proteins). Long or fibrous polypeptide chains generate constructions made up of filaments and sheets in fibrous proteins. Following are list fibrous protein example:

  • Keratin
  • Spider silk
  • Collagen
  • Type I Collagen
  • Type II Collagen
  • Type III Collagen
  • Type IV Collagen
  • Type V Collagen
  • Elastin
  • Fibrin
  • Laminins
  • Fibroin
  • Silk I
  • Silk II
  • Silk III
  • Myosin

Keratin

Keratin is a structurally fibrous protein that originates to the scleroprotein category. In vertebrates, alpha-keratin (-keratin) is a kind of keratin. This material is found in scales, hair, nails, hooves, feathers, horns, claws and the outer layer of skin in vertebrates.

Spider silk

Although spider silk is classed as keratin, the protein’s synthesis may have developed independently of vertebrate silk production.

Functions:

Chitin is perhaps the only biological substance that may approximate the hardness of keratinized tissue. Keratin also helps to protect epithelial cells from damages and stress.

The impala’s horns are comprised of keratin and have a bone core from wikipedia

Collagen

Collagen is the most essential structural protein in the extracellular environment, and it may be observed in all connective cells around the body. It contributes for 25 to 35 percent of total protein levels in animals, making it the most frequent protein.

Type I Collagen

Organs, bone, skin, tendon, vasculature (major component of the bone’s organic part)

Type II Collagen

Cartilage (cartilage’s major collagenous component)

Type III Collagen

Reticulate (the major component of reticular fibres) is a form of reticular fibre that is usually seen alongside type I.

Type IV Collagen

The basement membrane’s epithelium-secreted layer, basal lamina, is formed.

Type V Collagen

Hair, placenta and cell surfaces

Functions

It offers structural support to connective tissue’s extracellular space. It’s the ideal array for epidermis, tendons, ligaments, and bones because of its hardness and resistance to stretching.

Three left-handed procollagens (red, green, and blue) combine to generate a right-handed triple helical tropocollagen moleculefrom wikipedia

Elastin 

The ELN gene in humans translates for the protein elastin. In gnathostomes, elastin is an important extracellular matrix component (jawed vertebrates). It’s present in connective tissue and is very flexible, permitting many tissues in the body to revert to their former shape after being stretched or constricted.

When skin is poked or squeezed, elastin helps it restore its natural place. Elastin is a load-bearing tissue found in vertebrates’ bodies and is employed in locations where mechanical energy must be stored. Elastin is expressed by the ELN gene in humans.

Function:

Two elements are involved in elastic fibres, one of which is transcribed by the ELN gene. Hydrophobic amino acids like glycine and proline are abundant in the encoded protein, forming mobile hydrophobic areas bordered by crosslinks between lysine residues.

Stretched elastin from the aorta of a bovine from wikipedia

Fibrin

Fibrin (sometimes referred to as Factor Ia) is a fibrous, non-globular protein that aids in the clotting of blood. This material is formed when the protease thrombin acts on fibrinogen, causing it to polymerize. Polymerized fibrin forms a hemostatic plug or clot over a wound site when it joins forces with platelets.

fibrous protein example
The double-d segment of human fibrin has a crystal structure from wikipedia

Functions

Fibrin (also known as Factor Ia) is now a fibrous protein that helps blood clot. The effect of the enzyme protease thrombin on fibrinogen leads it to polymerize, resulting in this substance.

Laminins

Laminins are extracellular matrix proteins with a large molecular weight (400 to 900 kDa). They make up a large component of the basal lamina (one of the basement membrane’s layers), which acts as a protein network foundation for the most cells and organs.

The laminins, which influence cell differentiation, migration, and adhesion, are a significant and physiologically active basal lamina component.

This figure from wikipedia depicts the structure of laminins and their many bonds with other molecules

Function:

Entactin, fibronectin, and perlecan link laminins to type IV collagen networks, forming separate networks. They also bind cell membranes with integrin receptors and other plasma membrane molecules such as the dystroglycan glycoprotein complex and Lutheran blood group glycoprotein.

Fibroin

Fibroin is an insoluble protein present in the silk of Bombyx mori larvae and other moth species such as Antheraea, Cricula, Samia, and Gonometa. Silk comprises two primary proteins, sericin, and fibroin, with a glue-like covering of sericin wrapping two unique fibroin filaments termed brins in their raw condition.

Silk I

Silk I is the naturally occurring chemical form of fibroin produced by the silk glands of Bombyx mori.

Silk II

Silk II describes the set of fibroin units in spun silk, which is stronger and more commonly utilised in commercial applications.

Silk III

Silk III is a recently found fibroin structure. Silk III is mostly generated at an interface in fibroin solutions (i.e. air-water interface, water-oil interface, etc.).

Functions

Fibroin was already widely employed in the production of medicinal materials. Silk peptides can be isolated from silkworm cocoons or silk glands.

Myosin

Myosins are a group of motor proteins that play a key role in muscle movement and a variety of other eukaryotic motility events. They constitute ATP-dependent and are in control of motility based on actin.

Functions:

Multiple myosin II molecules work together to produce movement in skeletal muscle via a power stroke process powered by ATP hydrolysis energy.

Conclusion:

In the above article, we studied about different types fibrous proteins including Collagen, Keratin, Elastin, Fibrin, Myosin, Fibroin, Laminins and different properties related to these fibrous proteins.

Ganeshprasad DN

Hi....I am Ganeshprasad DN, completed my Ph.D. in Biochemistry from Mangalore University, I intend to use my knowledge and technical skills to further pursue research in my chosen field. LinkedIn : linkedin.com/in/d-n-ganeshprasad-157b8a107

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