title: In vitro molecular evolution yields an NEIBM with a potential novel IgG binding property.
abstract: Staphylococcus aureus protein A (SpA) and protein G of groups C and G streptococci (SpG) are two well-defined bacterial immunoglobulin (Ig)-binding proteins (IBPs) with high affinity for specific sites on IgG from mammalian hosts. Both SpA and SpG contain several highly-homologous IgG-binding domains, each of which possesses similar binding characteristic of the whole corresponding proteins. Whether specific combinations of these domains could generate a molecule with novel IgG-binding properties remained unknown. We constructed a combinatorial phage library displaying randomly-rearranged A, B, C, D and E domains of SpA as well as the B2 (G2) and B3 (G3) domains of SpG. In vitro molecular evolution directed by human, rabbit, bovine, or goat polyclonal IgGs and four subclasses of mouse monoclonal IgGs generated one common combination, D-C-G3. A series of assays demonstrated that D-C-G3 exhibited a potential novel IgG binding property that was obviously different from those of both parent proteins. This study provides an example of successful protein engineering through in vitro molecular evolution and useful approaches for structure and function studies of IBPs.
authors.affiliation: Department of Medical Microbiology and Parasitology, School of Basic Medicine, Second Military Medical University, Shanghai 200433, China.
authors.forename: Peipei
authors.initials: P
authors.lastname: Qi
authors.affiliation: Department of Medical Microbiology and Parasitology, School of Basic Medicine, Second Military Medical University, Shanghai 200433, China.
authors.forename: Ying-Ying
authors.initials: YY
authors.lastname: Ding
authors.affiliation: Department of Medical Microbiology and Parasitology, School of Basic Medicine, Second Military Medical University, Shanghai 200433, China.
authors.forename: Ting
authors.initials: T
authors.lastname: He
authors.affiliation: Fudan-Zhangjiang Bio-pharmaceutical Co., Ltd., Shanghai 201203, China.
authors.forename: Tong
authors.initials: T
authors.lastname: Yang
authors.affiliation: Department of Medical Microbiology and Parasitology, School of Basic Medicine, Second Military Medical University, Shanghai 200433, China.
authors.forename: Qiuli
authors.initials: Q
authors.lastname: Chen
authors.affiliation: Department of Medical Microbiology and Parasitology, School of Basic Medicine, Second Military Medical University, Shanghai 200433, China.
authors.forename: Jiaojiao
authors.initials: J
authors.lastname: Feng
authors.affiliation: Department of Medical Microbiology and Parasitology, School of Basic Medicine, Second Military Medical University, Shanghai 200433, China.
authors.forename: Jinhong
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Medical Microbiology and Parasitology, School of Basic Medicine, Second Military Medical University, Shanghai 200433, China.
authors.forename: Mingmei
authors.initials: M
authors.lastname: Cao
authors.affiliation: Department of Medical Microbiology and Parasitology, School of Basic Medicine, Second Military Medical University, Shanghai 200433, China.
authors.forename: Xiangyu
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Medical Microbiology and Parasitology, School of Basic Medicine, Second Military Medical University, Shanghai 200433, China.
authors.forename: Heng
authors.initials: H
authors.lastname: Peng
authors.affiliation: Department of Medical Microbiology and Parasitology, School of Basic Medicine, Second Military Medical University, Shanghai 200433, China.
authors.forename: Huaimin
authors.initials: H
authors.lastname: Zhu
authors.affiliation: Department of Medical Microbiology and Parasitology, School of Basic Medicine, Second Military Medical University, Shanghai 200433, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Cao
authors.affiliation: Department of Medical Microbiology and Parasitology, School of Basic Medicine, Second Military Medical University, Shanghai 200433, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Pan
mesh_terms: D000595:Amino Acid Sequence; D058846:Antibodies, Monoclonal, Murine-Derived / Q000302:isolation & purification*; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics*; D002846:Chromatography, Affinity; D019020:Directed Molecular Evolution; D015870:Gene Expression; D007074:Immunoglobulin G / Q000737:chemistry* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D019151:Peptide Library; D011485:Protein Binding; D013205:Staphylococcal Protein A / Q000096:biosynthesis / Q000235:genetics*
chemical_list: D058846:Antibodies, Monoclonal, Murine-Derived; D001426:Bacterial Proteins; C034284:IgG Fc-binding protein, Streptococcus; D007074:Immunoglobulin G; D019151:Peptide Library; D013205:Staphylococcal Protein A