title: Molecular basis of a million-fold affinity maturation process in a protein-protein interaction.
abstract: Protein engineering is becoming increasingly important for pharmaceutical applications where controlling the specificity and affinity of engineered proteins is required to create targeted protein therapeutics. Affinity increases of several thousand-fold are now routine for a variety of protein engineering approaches, and the structural and energetic bases of affinity maturation have been investigated in a number of such cases. Previously, a 3-million-fold affinity maturation process was achieved in a protein-protein interaction composed of a variant T-cell receptor fragment and a bacterial superantigen. Here, we present the molecular basis of this affinity increase. Using X-ray crystallography, shotgun reversion/replacement scanning mutagenesis, and computational analysis, we describe, in molecular detail, a process by which extrainterfacial regions of a protein complex can be rationally manipulated to significantly improve protein engineering outcomes.
authors.affiliation: Boston Biomedical Research Institute, 64 Grove Street, Watertown, MA 02472, USA.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Bonsor
authors.forename: Sandra
authors.initials: S
authors.lastname: Postel
authors.forename: Brian G
authors.initials: BG
authors.lastname: Pierce
authors.forename: Ningyan
authors.initials: N
authors.lastname: Wang
authors.forename: Penny
authors.initials: P
authors.lastname: Zhu
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Buonpane
authors.forename: Zhiping
authors.initials: Z
authors.lastname: Weng
authors.forename: David M
authors.initials: DM
authors.lastname: Kranz
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Sundberg
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D016296:Mutagenesis; D050505:Mutant Proteins / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D015202:Protein Engineering; D025941:Protein Interaction Mapping; D020836:Protein Structure, Quaternary; D011948:Receptors, Antigen, T-Cell / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D050505:Mutant Proteins; D011948:Receptors, Antigen, T-Cell