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A multi-block copolymer comprises at least one hydrophilic collagen-like block and at least one silk-like block. The silk-like block comprises an amino acid sequence ((GA) m GX) n , wherein G is glycine, A is alanine, m and n are at least 2. X is an ionizable amino acid. The ionizable amino acid is inducible to bear a positive charge or a negative charge. The ionizable amino acid bearing the positive charge is preferably histidine and the one bearing the negative charge is preferably glutamic acid.

Disclosed is a block co-polypeptide comprising at least two blocks T and at least one block S, with blocks T and S alternating, wherein each T independently denotes a Trimerizing Block being a polypeptide block capable of forming a thermoreversible collagen-like triple helix structure, and whereineach S independently denotes a Spacer Block S being a polypeptide neither forming a collagen-like triple helix. The block co-polypeptide is capable of forming a gel, and is useful as an animal-free, biocompatible substitute for gelatin. Uniquely, the polypeptide allows the independent controlling of the melting temperature of the gel, the stiffness and crosslink density of the gel, the lower critical gel-forming concentration related to the length of the molecules, and unrelated (e.g. biological, physiological, pharmaceutical or signalling) functions of the molecule.

De Biobased-Productsdivisie van AFSG-Wageningen UR gebruikt micro-organismen om op commando polymeren te maken met een van a tot z ontworpen monomeervolgorde en blokstructuur

The present invention relates to a method for the production of collagen-like compounds containing hydroxylated proline residues. Of specific interest is the production of recombinant collagen-like compounds in which hydroxylation of proline residues is achieved by a prolyl hydroxylase from a fungus, preferably a yeast, in particular Hansenula polymorpha. Also the invention concerns a method for controlling the hydroxylation of proline residues by such a prolyl hydroxylase characterised by the addition of collagen-like oligopeptides, such as gelatine hydrolysate, in particular gelatone or peptone.

Several yeast systems have recently been developed for the recombinant production of gelatin and collagen. Amino acid sequence-specific prolyl 4-hydroxylation is essential for the gel-forming capacity of gelatin and for the proper folding of (pro)collagen. This post-translational modification is generally considered to be absent in microbial eukaryotic systems and therefore co-expression of heterologous (human or animal) prolyl 4-hydroxylase would be required. However, we found that the well-known protein expression host Hansenula polymorpha unexpectedly does have the endogenous capacity for prolyl 4-hydroxylation. Without co-expression of a heterologous prolyl 4-hydroxylase, both an endogenous collagen-like protein and a heterologously expressed collagen fragment were found to be sequence-specifically hydroxylated.

A tabular silver halide emulsion wherein the tabular grains account for more than 75% of the total grain projected area said emulsion comprising silver halide grains nucleated in the presence of nucleation peptizer and thereafter grown in the presence of growth peptizer, wherein at least one of the peptizers is substantially pure collagen like material prepared by genetic engineering of native collagen encoding nucleic acid, said peptizer having an amino acid sequence comprising more than 4 different amino acids. A process of preparing the AgX emulsion. A process of producing recombinant collagen like polypeptide comprising expression of a collagen like polypeptide encoding nucleic acid sequence by a microorganism to a degree exceeding 0.95 grammes /liter, said recombinant collagen being free of helix structure and preferably the expression occurring in a microorganism other than E. coli or Saccaromyces cerevisiae.