See also “purification of antibodies” and “purification schemes”

See also Analogues/Derivatives/Mutagenesis/Variants     See also Resin regeneration

Staphylococcal protein A (SPA) is a protein that is found in nature anchored to the outer membrane of the gram-positive Staphylococcus aureus bacterium, the organisms which is commonly associated with medically significant human “Staph” infection. Functionally, SPA is well known for its ability to tightly, but reversibly bind to the constant region of IgG. This property has been widely used in the affinity purificaiton of antibodies. (Pyeser, US6,691,608).

Where Protein A Binds (epitopes): (see outline)

Recombinant production of Protein A

Recombinant production of Protein A in Gram positive bacterial strains is disclosed by Fahnestock in US4,617,266.  See also (Colbert, 5,151,350) for cloning of gene for protein A.

Jendeberg (J. Molecular Recognition, 8, 270-278 (1995) discloses that divalent (ZZ) forms of Protein A has a C terminal extension of 17 amino acids (VDANSRGSVDLQPSLSK).

Profy (US5,084,559) discloses modification of protein A gene to express a protein containing a single cysteine amino acid reisude at a defined position in the amino acid sequence. Protein A contains no cysteine residues in the WT.

Structure: see outline

Types of Media/Resins: See outline

Resin Regeneration See outline

Conditions/ Parameters: See outline

Applications

Streptavidin-Protein A chimeric Proteins: Sano (US 5328985) discloses a sterptavidin-Protein A chimeric protein in which the streptavidin binds biotin and the Protein A binds an antibody. Accordingly, one side specificity is caused by high affinity bind of the Protein A side to antibody molecules and the second side specificity is cuased by high affinity binding of the streptavidin side to any target biological material which contains biotin or which is capable of being biotinylated. The fusion protein can be used to purify target molecules onto solid supports. 

Biotin-Protein A chimeric Proteins: Patchornik (US20080108053) also discloses an antibody binding moiety such as protein A which is attached to at least one corrdinating moeity such as biotin. In order to initiate purification, the ligand attached to the coordinating moeity is added to the sample, allowing binding of the target molecule to the ligand and then a coordinator ion or molecule such as a metal is added to allow precipitation.