Fibrous proteins, also called scleroproteins, are long filamentous protein molecules that form one of the two main classes of tertiary structure protein (the other being globular proteins). Fibrous proteins are only found in animals. A filament is a fine, thinly spun thread, fiber, or wire. ... In chemistry, a molecule is an aggregate of at least two atoms in a definite arrangement held together by special forces. ... In biochemistry, the tertiary structure of a protein is its overall shape. ... Globular proteins, or spheroproteins are one of the two main protein classes, comprising globelike proteins that are more or less soluble in aqueous solutions (where they form colloidal solutions). ... Phyla Subregnum Parazoa Porifera (sponges) Subregnum Agnotozoa Placozoa (trichoplax) Orthonectida (orthonectids) Rhombozoa (dicyemids) Subregnum Eumetazoa Radiata (unranked) (radial symmetry) Ctenophora (comb jellies) Cnidaria (coral, jellyfish, anemones) Bilateria (unranked) (bilateral symmetry) Acoelomorpha (basal) Myxozoa (slime animals) Superphylum Deuterostomia (blastopore becomes anus) Chordata (vertebrates, etc. ...

Fibrous proteins form 'rod' or 'wire' -like shapes and are usually inert structural or storage proteins. They are generally water-insoluble and are found as an aggregate due to hydrophobic R-groups that stick out of the molecule. The amino acid sequences they are made from often have limited residues with repeats. These can form unusual secondary structures, e.g. collagen triple helix. The structures often contain 'cross-links' between chains, for example cys-cys disulfide bonds between keratin chains. In English, to be inert is to be in a state of doing little or nothing. ... A substance is soluble in a fluid if it dissolves in that fluid. ... Look up Aggregate in Wiktionary, the free dictionary. ... A residue, broadly, is anything left behind by a reaction or other process. ... A representation of the 3D structure of the Myoglobin protein. ... Tropocollagen triple helix. ... A helix (pl: helices), from the Greek word έλικας/έλιξ, is a twisted shape like a spring, screw or a spiral staircase. ...

Fibrous proteins are usually used to construct connective tissues, tendons, bone matrix and muscle fiber.

Examples of fibrous proteins include keratins, collagens and elastins. Microscopy of keratin filaments inside cells. ... Tropocollagen triple helix. ... Elastin, also known as elasticin, is a protein in connective tissue that is elastic and allows skin to return to its original position when it is poked or pinched. ...