The present invention relates to a biopolymer having excellent tensile strength, extensibility and toughness. The present invention further relates to a nucleic acid molecule encoding the biopolymer of the invention, a vector comprising the nucleic acid molecule of the invention and a non-human host transformed with the vector of the invention. Furthermore, the present invention relates to methods for producing a biopolymer of the invention and to foams, films, gels, coatings, particles, capsules, springs or nonwoven mats as well as fibers comprising or consisting of the biopolymer of the invention. The present invention also relates to a method of producing fibers and the biopolymer of the invention for use in medicine, agriculture, cosmetics as well as surface, paper, leather and/or textile processing.