Spider silks are the most robust biological materials in nature. This characteristic generates enormous interest in engineering silk-based biomaterials for industrial applications. Among the seven silk types spun by orb-weaving spiders, dragline from major ampullate (MA) glands is the most studied for its high tensile strength and toughness.
Dragline silk of Darwin’s bark spider (Caerostris darwini) from Madagascar is one of the most durable silk.
Now, a team of international scientists has recently discovered a previously complex protein in the strongest known spider web material. Scientists found that C. darwini dragline-producing major ampullate glands highly express a novel silk gene transcript encoding a protein that diverges markedly from closely related proteins and contains abundant proline, known to confer silk extensibility.
Past research has shown that the spider makes seven different kinds of silk for use in different parts of its web. Among them, Dragline is known to be the strongest spider silk in existence.
Highlighting this, scientists took a gander at the dragline silk and the gland that produces it.
They found two familiar types of spindroins—types of repetitive proteins—called MaSp1 and MaSp2, which are found in many spider silks. But in the dragline from Darwin’s bark spiders, they found another spindroin, which they named MaSp4a.
The protein contains high quantities of an amino acid called proline, which prior research has shown is generally associated with elasticity. The protein also had less of some of the other components found in MaSp1 and MaSp2, which made it unique.
Scientists also found that the ampullae gland- responsible for silk generation- is longer than in other spiders. However, the discovery offers another clue to the strength of the silk that is produced.
Scientists published their findings in the journal Communications Biology.