Novel beta-galactoside-alpha2, 6-sialyltransferase, a gene encoding thereof, and a method for producing thereof

An isolated nucleic acid encoding a protein having β-galactoside-α2,6-sialyltransferase activity, wherein the protein comprises:

• (a) an amino acid sequence comprising deletion, substitution, insertion and/or addition of one or more amino acids in an amino acid sequence selected from the group consisting of SEQ ID NO:
• 2, amino acid residues 15-514 of SEQ ID NO:
• 2, SEQ ID NO:
• 4 and SEQ ID NO:
• 12;
• or
• (b) an amino acid sequence sharing an identity of 60% or more with an amino acid sequence selected from the group consisting of SEQ ID NO:
• 2, amino acid residues 15-514 of SEQ ID NO:
• 2, SEQ ID NO:
• 4 and SEQ ID NO:
• 12.

An isolated nucleic acid comprising a nucleotide sequence selected from the group consisting of SEQ ID NO:

• 1, nucleotides 43-1545 of SEQ ID NO:
• 1, SEQ ID NO:
• 3 and SEQ ID NO:
• 11.

An isolated nucleic acid encoding a protein having β-galactoside-α2,6-sialyltransferase activity, wherein the nucleic acid comprises:

• (a) a nucleotide sequence comprising deletion, substitution, insertion and/or addition of one or more nucleotides in a nucleotide sequence selected from the group consisting of SEQ ID NO:
• 1, nucleotides 43-1545 of SEQ ID NO:
• 1, SEQ ID NO:
• 3 and SEQ ID NO:
• 11;
• (b) a nucleotide sequence sharing an identity of 70% or more with a nucleotide sequence selected from the group consisting of SEQ ID NO:
• 1, nucleotides 43-1545 of SEQ ID NO:
• 1, SEQ ID NO:
• 3 and SEQ ID NO:
• 11;
• or
• (c) a nucleotide sequence hybridizable under stringent conditions with the complementary strand of a nucleotide sequence selected from the group consisting of SEQ ID NO:
• 1, nucleotides 43-1545 of SEQ ID NO:
• 1, SEQ ID NO:
• 3 and SEQ ID NO:
• 11.

An isolated microorganism belonging to the genus Photobacterium, which expresses a protein comprising an amino acid sequence selected from the group consisting of SEQ ID NO:

• 2, amino acid residues 15-514 of SEQ ID NO:
• 2, SEQ ID NO:
• 4 and SEQ ID NO:
• 12.

A method for producing a protein having β-galactoside-α2,6-sialyltransferase activity, which comprises the following steps:

• 1) culturing a microorganism producing a β-galactoside-α2,6-sialyltransferase comprising an amino acid sequence selected from the group consisting of SEQ ID NO:
• 2, amino acid residues 15-514 of SEQ ID NO:
• 2, SEQ ID NO:
• 4 and SEQ ID NO:
• 12;
• and
• 2) isolating the β-galactoside-α2,6-sialyltransferase from the cultured microorganism or the culture supernatant.