Patent ID: 8377671

Claim:
A process for obtaining a mutant polynucleotide encoding a modified large subunit of a wild-type O 2 sensitive [NiFe]-hydrogenase, for improving dioxygen tolerance of said [NiFe]-hydrogenase, wherein said process comprises: providing an initial polynucleotide comprising a sequence encoding a large subunit of a wild-type O 2 sensitive [NiFe]-hydrogenase having a hydrogenase activity, 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 at least the residues X 2 of motif L2 of said large subunit by a methionine.