Proximity-based sortase-mediated protein purification and ligation

1. A conjugate protein composition comprising a first protein and a second protein, wherein:

(i) said first protein comprises a protein of interest in series with a sortase recognition sequence and a first binding pair partner; wherein:

said protein of interest is N-terminal and connected via a linker to said sortase recognition sequence and said sortase recognition sequence is N-terminal and connected via a linker to said first binding pair partner; or

said first binding pair partner is N-terminal and connected via a linker to said sortase recognition sequence and said sortase recognition sequence is N-terminal and connected via a linker to said protein of interest;

and

(ii) said second protein comprises a second binding pair partner in series with a sortase and a first affinity tag having a selective affinity for a first affinity tag resin, wherein:

said second binding pair partner is N-terminal and connected via a linker to said sortase and said sortase is N-terminal and connected via a linker to said first affinity tag; or

said sortase is N-terminal and connected via a linker to said second binding pair partner and said second binding pair partner is N-terminal and connected via a linker to said first affinity tag; or

said first affinity tag is N-terminal and connected via a linker to said second binding pair partner and said second binding pair partner is N-terminal and connected via a linker to said sortase; or

said first affinity tag is N-terminal and connected via a linker to said sortase and said sortase is N-terminal and connected via a linker to said second binding pair partner;

wherein said first binding pair partner and said second binding pair partner comprise two protein moieties that form a first heterodimer selected from the group consisting of SpyCatcher and SpyTag; two complementary halves of a split intein; c-Jun and c-Fos; leucine zippers; split adhesin domains; SnoopCatcher and SnoopTag; S-protein and S-Tag; Streptavidin/Streptactin or variants thereof and Strep-tag or Strep-tag II; calmodulin and calmodulin binding peptide; and a binding pair of a dock-and-lock system.

2. A conjugate protein composition comprising a first protein, a second protein, and a third protein, wherein:

(a) the first protein comprises an antibody of interest or an antigen-binding fragment thereof with

(i) a first antibody sortase recognition construct C-terminal and connected via a linker to at least one heavy chain of the antibody or antigen-binding fragment thereof and comprising a first antibody sortase recognition sequence and a first antibody binding pair partner; and

(ii) a second antibody sortase recognition construct C-terminal and connected via a linker to at least one light chain of said antibody or antigen-binding fragment thereof and comprising a second antibody sortase recognition sequence and a second antibody binding pair partner;

(b) the second protein comprises a first binding pair partner in series with a first sortase and an affinity tag having a selective affinity for a first affinity tag resin, wherein the first antibody binding pair partner and the first binding pair partner form a first heterodimer selected from the group consisting of SpyCatcher and SpyTag; two complementary halves of a split intein; c-Jun and c-Fos; leucine zippers; split adhesin domains; SnoopCatcher and SnoopTag; S-protein and S-Tag; Streptavidin/Streptactin or variants thereof and Strep-tag or Strep-tag II; calmodulin and calmodulin binding peptide; and a binding pair of a dock-and-lock system, and wherein:

said first binding pair partner is N-terminal and connected via a linker to said first sortase and said first sortase is N-terminal and connected via a linker to said first affinity tag; or

said first sortase is N-terminal and connected via a linker to said first binding pair partner and said first binding pair partner is N-terminal and connected via a linker to said first affinity tag; or

said first affinity tag is N-terminal and connected via a linker to said first binding pair partner and said first binding pair partner is N-terminal and connected via a linker to said first sortase; or

said first affinity tag is N-terminal and connected via a linker to said first sortase and said first sortase is N-terminal and connected via a linker to said first binding pair partner;

and

(c) the third protein comprising a second binding pair partner in series with a second sortase and a second affinity tag, wherein said second antibody binding pair partner and said second binding pair partner comprise two protein moieties that form a second heterodimer selected from the group consisting of SpyCatcher and SpyTag; two complementary halves of a split intein; c-Jun and c-Fos; leucine zippers; split adhesin domains; SnoopCatcher and SnoopTag; S-protein and S-Tag; Streptavidin/Streptactin or variants thereof and Strep-tag or Strep-tag II; calmodulin and calmodulin binding peptide; and a binding pair of a dock-and-lock system, and wherein:

said second binding pair partner is N-terminal and connected via a linker to said second sortase and said second sortase is N-terminal and connected via a linker to said second affinity tag; or

said second sortase is N-terminal and connected via a linker to said second binding pair partner and said second binding pair partner is N-terminal and connected via a linker to said second affinity tag; or

said second affinity tag is N-terminal and connected via a linker to said second binding pair partner and said second binding pair partner is N-terminal and connected via a linker to said second sortase; or

said second affinity tag is N-terminal and connected via a linker to said second sortase and said second sortase is N-terminal and connected via a linker to said second binding pair partner.

3. The conjugate protein composition of claim 1 , wherein said first protein further comprises a second affinity tag having a selective affinity for a second affinity tag resin.

4. The conjugate protein composition of claim 1 , wherein said sortase is selected from the group consisting of sortase A (SrtA), sortase B (SrtB), sortase C (SrtC), sortase D (SrtD), sortase E (SrtE), sortase F (SrtF), and variants a variant thereof.

5. The conjugate protein composition of claim 1 , wherein the sortase recognition sequence is selected from the group consisting of LPXTG (SEQ ID NO: 1), LPKTG (SEQ ID NO: 2), LPATG (SEQ ID NO: 3), LPNTG (SEQ ID NO: 4), LPETG (SEQ ID NO: 5), LPXAG (SEQ ID NO: 6), LPNAG (SEQ ID NO: 7), LPXTA (SEQ ID NO: 8), LPNTA (SEQ ID NO: 9), LGXTG (SEQ ID NO: 10), LGATG (SEQ ID NO: 11), IPXTG (SEQ ID NO: 12), IPNTG (SEQ ID NO: 13), IPETG (SEQ ID NO: 14), NPQTN (SEQ ID NO: 15), LAXTG (SEQ ID NO: 16), LPXSG (SEQ ID NO: 17), LSETG (SEQ ID NO: 18), LPXCG (SEQ ID NO: 19), LPXAG (SEQ ID NO: 20), and XPETG (SEQ ID NO: 21).

6. The conjugate protein composition of claim 1 , wherein the first affinity tag is selected from the group consisting of a histidine tag (His tag), a chitin-binding domain, a calmodulin tag, a polyglutamate tag, a maltose binding protein, glutathione-S-transferase, an S-tag, SBP-tag, Strep-tag, Strep-tag II, green fluorescent protein-tag, thioredoxin tag, Nus-tag, Fc-tag, Halo-tag, FLAG-tag, V5-tag, VSV-tag, Xpress tag, E-tag, Myc-tag, HA-tag, Softag, and NE-tag, biotin (via biotin ligase), BirA, AviTag, BCCP, SpyTag, SpyCathcher, SnoopTag, and SnoopCatcher.

7. The conjugate protein composition of claim 6 , further comprising the first affinity tag resin to which said affinity tag selectively binds.