In today's #JolasFavouriteProteins I will tweet about my all time favourite protein - spider silk, my undying love. Thread! (haha) #AcademicChatter

Spiders spin 7 different silks with wildly different properties, and I will be focusing on the major ampullate silk, or MaSp.

Silk is the toughest elastomeric protein to rule them all. It is nearly indestructible by strong acids, bases, solvents, boiling water, and even biodegradation rates of silk are very slow. The best silk feature - mammalian body doesn't recognise silk as a foreign object.

As all elastomers, silk is a disordered, glycine-rich, and repetitive protein, plus it has loads of distinguishing features.
First, it's absolutely massive (>250kDa) compared to an average protein (~50kDa).

Next, it is composed of two distinct non-repetitive regions flanking the repetitive core. Besides glycine, silk core is rich in alanine blocks that assemble into so-called 'liquid crystal' structure providing the unbelievable toughness of the fibre.

Non-repetitive regions help silk to stay soluble despite its very, really hydrophobic nature, and contain nucleation points for fibre formation.

Silk's modular nature allows us to mix and match its motifs like lego to build tailored synthetic silk, eg with good water solubility or the ability form fibres in vitro. The building blocks can be mixed with another bioactivity, such as cell adhesion or antimicrobial activity.

Synthetic silks have been produced in bacteria, yeast, plants, cell culture, silkworms, and even goats (milk; not hair).

To conclude, spiders are a great thing to research due to an invariably strong reaction of the public (love it or hate it). Silk is a truly phenomenal material, and I hope that within the next decade, recombinant spider silk materials will hit the mass market.