NiFe-hydrogenases having an improved resistance to dioxygen, process for obtaining them and their applications

摘要

The invention relates to [NiFe]-hydrogenases having an improved resistance to dioxygen, said [NiFe]-hydrogenases may be obtained by:
- providing an initial polynucleotide comprising a sequence encoding a large subunit of a [NiFe]-hydrogenase, said large subunit comprising the following peptide motifs:
€¢ L1: RGXE, wherein X = L, I, F, V or M
€¢ L2: [R/K]X 1 C[G/R]X 2 C, wherein X 1 is any amino acid residue, X 2 = L, V, I or M; L1 and L2 being separated by 16 any amino acid residues;
€¢ L3: X 1 X 2 X 3 X 4 X 5 X 6 X 7 X 8 X 9 X 10 X 11 X 12 [D/S/E], wherein X 1 = D, S, N or E, X 2 = H, D, S, N or L, X 5 = H, S, A, Q or W, X 6 = F, T, Y or G, X 9 = L, F, M or Y, the other X n being any amino acid residue;
€¢ L4: D[P/I/S]CX 1 X 2 CX 3 X 4 [H/R], wherein X 2 = A,S,V,G or T, X 1 , X 3 and X 4 are any amino acid residue
€¢ and optionally comprising a motif L0: R[I/V/A]EG[H/D/A].
- modifying said initial polynucleotide in order to substitute the residue X 2 of motif L2 and/or the residue X 4 and/or the residue X 9 of motif L3 of said large subunit by methionine(s).