Protein having fermented milk viscosity improving effect, fermented milk using the same and method for producing the same

A composition comprising:

• at least one selected from the group consisting of DNAs encoding the proteins (a) to (d):
• (a) a protein which is composed of an amino acid sequence set forth in SEQ ID NO:
• 1;
• (b) a protein which is, in the amino acid sequence set forth in SEQ ID NO:
• 1, composed of an amino acid sequence in which one or more amino acids other than tyrosine at position 40 are substituted, deleted, inserted, and/or added and has a fermented milk viscosity improving effect;
• (c) a protein which is composed of an amino acid sequence having 80% or more identity with the amino acid sequence set forth in SEQ ID NO:
• 1, has tyrosine as an amino acid corresponding to position 40 of the amino acid sequence set forth in SEQ ID NO:
• 1, and has a fermented milk viscosity improving effect;
• and
• (d) a protein which is composed of an amino acid sequence encoded by a DNA that hybridizes under stringent conditions with a complementary strand of a DNA composed of the nucleotide sequence set forth in SEQ ID NO:
• 2, has tyrosine as an amino acid corresponding to position 40 of the amino acid sequence set forth in SEQ ID NO:
• 1, and has a fermented milk viscosity improving effect.

A vector comprising:

• at least one selected from the group consisting of DNAs encoding the proteins (a) to (d):
• (a) a protein which is composed of an amino acid sequence set forth in SEQ ID NO:
• 1,
• (b) a protein which is, in the amino acid sequence set forth in SEQ ID NO:
• 1, composed of an amino acid sequence in which one or more amino acids other than tyrosine at position 40 are substituted, deleted, inserted, and/or added and has a fermented milk viscosity improving effect
• (c) a protein which is composed of an amino acid sequence having 80% or more identity with the amino acid sequence set forth in SEQ ID NO:
• 1, has tyrosine as an amino acid corresponding to position 40 of the amino acid sequence set forth in SEQ ID NO:
• 1, and has a fermented milk viscosity improving effect and
• (d) a protein which is composed of an amino acid sequence encoded by a DNA that hybridizes under stringent conditions with a complementary strand of a DNA composed of the nucleotide sequence set forth in SEQ ID NO:
• 2, has tyrosine as an amino acid corresponding to position 40 of the amino acid sequence set forth in SEQ ID NO:
• 1, and has a fermented milk viscosity improving effect.

A method for evaluating lactic acid bacteria for presence or absence of a fermented milk viscosity improving effect using as an index at least one selected from the group consisting of DNAs encoding the following proteins (a) to (d):

• (a) a protein which is composed of an amino acid sequence set forth in SEQ ID NO:
• 1;
• (b) a protein which is, in the amino acid sequence set forth in SEQ ID NO:
• 1, composed of an amino acid sequence in which one or more amino acids other than tyrosine at position 40 are substituted, deleted, inserted, and/or added and has a fermented milk viscosity improving effect;
• (c) a protein which is composed of an amino acid sequence having 80% or more identity with the amino acid sequence set forth in SEQ ID NO:
• 1, has tyrosine as an amino acid corresponding to position 40 of the amino acid sequence set forth in SEQ ID NO:
• 1, and has a fermented milk viscosity improving effect;
• and
• (d) a protein which is composed of an amino acid sequence encoded by a DNA that hybridizes under stringent conditions with a complementary strand of a DNA composed of the nucleotide sequence set forth in SEQ ID NO:
• 2, has tyrosine as an amino acid corresponding to position 40 of the amino acid sequence set forth in SEQ ID NO:
• 1, and has a fermented milk viscosity improving effect.