High affinity metal-oxide binding peptides with reversible binding

Abstract

A dodecamer peptide, and its modified variant, having a repeating glycine-lysine sequence was created and formed to bind with high affinity to oxide surfaces and certain activated polymeric surfaces. Reversible binding characteristics of the peptides were demonstrated. The peptides were integrated with proteins, cells and fusion proteins to provide attachment of the proteins, cells and fusion proteins to solid material structures. The peptides can be used to functionalize surfaces of components within mechanical, biomechanical, micro fluid, electronic, bio electronic, bio-optical, and biochemical devices. Experiments were canied out to assess functionalization and reusability of a suspended mass resonator's cantilever.

1 - 60 . (canceled) 
     
     
         61 . A method comprising treating an oxide or plasma-activated surface with a peptide that bind with the oxide or plasma-activated surface, wherein the peptide exhibits a binding affinity to a sapphire surface with a dissociation constant of about 1 nanomolar to about 100 nanomolar. 
     
     
         62 . The method of  claim 61 , wherein the peptide includes a number of charged groups separated by at least one neutral amino acid. 
     
     
         63 . The method of  claim 61 , wherein the peptide has a backbone including a number of charged groups that aligns amino acids towards the surface so that the charged groups within the peptide can undergo local electrostatic interactions with the surface. 
     
     
         64 . The method of  claim 61 , wherein the peptide includes a plurality of lysine or arginine residues separated by neutral residues. 
     
     
         65 . The method of  claim 61 , wherein the peptides are integrated with proteins. 
     
     
         66 . The method of  claim 61  wherein the peptides are integrated with fusion proteins. 
     
     
         67 . The method of  claim 61  wherein the peptides are integrated with cells. 
     
     
         68 . A method for purifying a protein containing an affinity peptide tag comprising contacting the protein containing the affinity peptide tag with a metal oxide and a solid support. 
     
     
         69 . The method of  claim 68 , wherein the affinity peptide tag includes a number of charged groups separated by at least one neutral amino acid. 
     
     
         70 . The method of  claim 68 , wherein said contacting step is carried out in a solution having an ionic strength of less than 350 mM. 
     
     
         71 . The method of  claim 68 , wherein the affinity peptide has a sequence GKGKGKGKGKGK (SEQ ID NO: 1) or GKGKGKGKGKGKASGKGKGKGKGKGK (SEQ ID NO: 2), comprising contacting the proteins or peptides with a metal oxide-based resin according to claim  1 . 
     
     
         72 . The method of  claim 68 , wherein the metal oxide is silica or alumina. 
     
     
         73 . The method of  claim 68 , further comprising eluting the protein by contacting the solid support with a solution having an ionic strength greater than resin above 350 mM. 
     
     
         74 . A method for removing a tagged protein from a solution comprising:
 (a) applying the solution to a metal oxide chromatography column, thereby binding the tagged protein binds to the column;   (b) collecting an effluent which is substantially free of the tagged protein;   (c) increasing the ionic strength of the metal oxide chromatography column above 350 mM to dissociate the tagged protein from the metal oxide chromatography column;   (d) collecting a resultant flow-through fraction of the solution containing the protein.