POLYPEPTIDE HAVING THE ABILITY TO FORM CONNECTIONS OF GLUCOSYL UNITS IN ALPHA-1,3 ON AN ACCEPTOR

1 . An isolated polypeptide having the ability to form specifically connections of glucosyl units in alpha-1,3 on an acceptor comprising at least one hydroxyl moiety and characterised in that said polypeptide comprises:

i) the pattern I of sequence SEQ ID no 1

ii) the pattern II of sequence SEQ ID no 2

iii) the pattern III of sequence SEQ ID no 3

iv) the pattern IV of sequence SEQ ID no 4

or derivatives of one or more of said domains having at least 80% identity with them; wherein said polypeptide furthermore has the aspartic residue (D) in position 5 of the pattern II (SEQ ID no 2), the glutamic acid residue (E) at position 6 of the pattern III (SEQ ID no 3) and the aspartic acid residue (D) in position 6 of the pattern IV (SEQ ID no 4).

2 . The isolated polypeptide according to claim 1 , characterised in that said polypeptide comprises the sequence SEQ ID no 6, an orthologue, a derivative, or a fragment thereof.

3 . The polypeptide according to claim 1 , characterised in that said polypeptide comprises or consists of the sequence SEQ ID no 9, an orthologue, a derivative, or a fragment thereof.

4 . The polypeptide according to claim 1 , characterised in that said orthologue is selected from the group comprising the sequences SEQ ID no 15 and SEQ ID no 17.

5 . An isolated polynucleotide encoding a polypeptide according to claim 1 , preferably said polynucleotide is defined by the sequence SEQ ID no 10.

6 . An expression vector comprising a polynucleotide as defined in claim 5 .

7 . A transformed host cell including an expression vector as defined in claim 6 .

8 . A composition comprising at least one polypeptide as defined in claim 1 , a polynucleotide encoding said polypeptide, a vector comprising said polynucleotide or a transformed host cell including said vector.

9 . A method of producing a polypeptide as defined in any one of claim 1 , said method including the steps of:

a) inserting a polynucleotide encoding said polypeptide or a vector comprising said polynucleotide into a host cell;

b) culturing said cell obtained in step a); and

c) extracting the polypeptide from the culture obtained in step b).

10 . A process for producing acceptors connected to glucosyl units in alpha 1,3 comprising a rate of connections of such glucosyl units in alpha 1,3 between 1 and 50%, said method comprising the steps of:

i) mixing in a reaction medium a polypeptide as defined in claim 1 , a substrate of said polypeptide and an acceptor comprising at least one hydroxyl moiety; and

ii) incubating said mixture obtained in step i) so as to obtain the connection of glucosyl units in alpha-1,3 on said acceptor.

11 . The method according to claim 10 , characterised in that the concentrations of substrate and of acceptor are adjusted so to get a connection rate between 35 and 50%.

12 . The method according to claim 10 , characterised in that the concentrations of substrate and of acceptor are adjusted so to get a connection rate of 20 to 35%.

13 . The method according to claim 10 , characterised in that the concentrations of substrate and of acceptor are adjusted so to get a connection rate lower than 20%.

14 . The method according to claim 1 , characterised in that said acceptor connected to glucosyl units in alpha-1,3 is selected from the group of polysaccharides, preferably glucans, including α-glucans such as dextran, dextrans branched in α-1,2, alternans, mutans, reuterans, starch, amylopectin, amylose, glycogen and pullulan.

15 . The method according to claim 10 , characterised in that the substrate is selected from the group comprising α-D-glucopyranosyl fluoride, p-nitrophenyl α-D-glucopyranoside, α-D-glucopyranosyl, α-L-sorofuranoside, lactulosucrose and sucrose.

16 . An acceptor connected to glucosyl units in alpha-1,3 likely to be obtained by the method according to claim 11 .

17 . A method for the production of acceptors connected to glucosyl units in alpha-1,3, comprising:

i) mixing in a reaction medium:

a polypeptide as defined in claim 1 , of a polynucleotide encoding said polypeptide, of a vector comprising said polynucleotide, of a host cell including said vector and/or a composition comprising said polypeptide, said polynucleotide, said vector, or said host cell,

a substrate of said polypeptide, and

an acceptor comprising at least one hydroxyl moiety; and

ii) incubating said mixture obtained in step i) so as to obtain the connection of glucosyl units in alpha-1,3 on said acceptor.

18 . A composition comprising an acceptor connected to glucosyl units in alpha-1,3 as defined in claim 16 as a thickener, emulsifier and/or stabiliser, wherein said composition is a formulation selected from the group consisting of food industrial, cosmetic, agrochemical, petrochemical and pharmaceutical formulations.

19 . A method of providing a prebiotic effect comprising administering to a subject in need there of an effective amount of an acceptor connected to glucosyl units in alpha-1,3 as defined in claim 16 as an agent with prebiotic effect.