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also at temperatures up to 125 °C. It is also degraded by proteolytic enzymes as other

proteins. The fluorescent properties have been reported to be pH dependent.

Genetic Engineering

Resilin protein biomaterials can be generated by genetic engineering of resilin-

encoding genes. Exon 1 from resilin is critical for its resilience properties. The

recombinant protein made from Exon 1 encoding the N-terminal domain in native

resilin as cloned and expressed is a 30 KD soluble protein in Escherichia Coli

which exhibited resilience closer to original resilin [13]. This sample had up to 92%

resilience and could be stretched to over 300% of its original length before breaking

[14]. A full-length recombination protein of Exons 1, 2 and 3 also exhibited elastic

properties closer to the Partial clone. r-Resilin can be stretched more than twice their

original length and recover more than 90% of the deformation energy once stretching

force is removed [15]. Resilin is mainly unstructured and forms terms as well as more

extended structures [16]. The polymers displayed adhesive properties.

Applications of Resilin

• Resilin is a protein of high elastomeric property having about 97% efficiency in

energy conversion.

• It has to last for the lifetime of the insect and hence cannot degrade but may get

modified as per the insect adaptations.

• It does not undergo tearing or fatigue even under stress conditions except in

foraging insects where it gets damaged.

• It has greater elasticity than rubber and is easy to produce under natural conditions.

Hence, it is the best possible substitute for rubber.

• Both neurogenic and myogenic insects have resilin at the fulcrum causing low or

high wingbeat frequency.

• The mechanical and biological properties of resilin can be readjusted by using

protein engineering including synthetic muscles, vocal cords, cardio-vascular,

semi-lunar valves and soft cartilage.

Thus resilin has great importance in biological industry and biomedical applica-

tions.

Silk

Silk is an important raw material for textiles and other goods with unique properties

as a natural fibre. The term silk in general is applicable to threads spun by certain

caterpillars, spiders and mussels. It plays an important role in protein chemistry,