Polysaccharide binding fusion proteins and conjugates

A composition comprising:

• a .beta.-1,4-glycan polysaccharide matrix and a hybrid protein comprising a polypeptide and an amino acid sequence derived from a polysaccharidase which binds to said .beta.-1,4-glycan polysaccharide matrix, wherein said hybrid protein comprises a cleavage site inserted between said polypeptide and said amino acid sequence, wherein said amino acid sequence is essentially lacking in hydrolytic activity, and wherein said composition is obtained by a method comprising binding said hybrid protein in a culture broth or a lysate of microbial cells expressing a DNA construct encoding said hybrid protein to said .beta.-1,4-glycan polysaccharide matrix.

In a method for binding a compound to a .beta.-1,4-glycan matrix, wherein said method comprises linking said compound to an agent which binds to said .beta.-1,4-glycan matrix to form a conjugate;

• and contacting said conjugate with said .beta.-1,4-glycan matrix, whereby said conjugate binds to said .beta.-1,4-glycan matrix, the improvement which comprises:
• using as said agent an amino acid sequence derived from a polysaccharidase which binds to said .beta.-1,4-glycan matrix, wherein said amino acid sequence is essentially lacking in hydrolytic activity.

A method for purifying a polypeptide, said method comprising:

• contacting a fusion protein comprising said polypeptide and a polysaccharide binding domain derived from a polysaccharidase and lacking in hydrolytic activity, with a matrix comprising a polysaccharide to which said polysaccharide binding domain binds to form a fusion protein-polysaccharide complex;
• and separating said polypeptide from said matrix comprising said polysaccharide.

A composition comprising:

• as components (1) a conjugate comprising (a) a first polypeptide or a chemical moiety joined to (b) a second polypeptide having an amino acid sequence comprising a substrate binding region of an enzyme selected from the group consisting of a cellulase, a chitinase, a xylanase, and an amylase which binds to a substrate for said enzyme, wherein said second polypeptide is derived from said enzyme and is essentially lacking in hydrolytic activity of said enzyme;
• and (2) a substrate for said enzyme, wherein component (1) is bound to component (2) via (b).

A composition comprising as components (a) a label comprising a first polypeptide or a chemical moiety joined to (b) a second polypeptide comprising an amino acid sequence comprising a substrate binding region derived from an enzyme selected from the group consisting of a cellulase, a chitinase, a xylanase and an amylase, wherein said amino acid sequence binds to a substrate for said enzyme and is essentially lacking in hydrolytic activity of said enzyme.

A modified surface comprising a plurality of conjugates bound to a surface of a solid support, wherein a conjugate comprises as components (a) a first polypeptide joined to (b) a second polypeptide having an amino acid sequence comprising a substrate binding region of an enzyme selected from the group consisting of a cellulase, a chitinase, a xylanase and an amylase which binds to a substrate for said enzyme, wherein said second polypeptide is essentially lacking in hydrolytic activity of said enzyme, and wherein said solid support comprises a substrate for said enzyme, wherein said first polypeptide is essentially lacking in hydrolytic activity of said enzyme.

A composition comprising a conjugate of a first polypeptide and a second polypeptide, wherein said second polypeptide comprises an amino acid sequence comprising a substrate binding region of an enzyme selected from the group consisting of cellulase, a chitinase, a xylanase and an amylase, which binds to a substrate for said enzyme, and wherein said second polypeptide is essentially lacking in hydrolytic activity of said enzyme.